Page broken on Apple devices

OK, this is an odd one so I’ll give all the info I can.

My staging site works fine on all devices but when I push it live, it fails on iPhone/iPad (all browsers) and when using Safari on macOS. The live site works in Chrome on macOS.

If I disable LiteSpeed, the site works across all devices.

If I leave LiteSpeed enabled but revert the .htaccess to the WordPress default, the site works. It’s worth noting that the .htaccess that fails on the live site is identical to the .htaccess that works on the staging site.

Sometimes the home page will load almost correctly (missing the image). Sometimes a single page will seem to load correctly. In both cases, other pages remain broken. They display as though the CSS is missing.

I looked at similar posts and found that users were reporting this problem if JS HTTP/2 Push is active, which it was. So I set that to inactive, but the issue remains. CSS HTTP/2 Push was already inactive.

Another related post spoke of 404 getting errors. I am getting 404 errors on /wp-content/litespeed/cssjs/f5bb9.js and /wp-content/litespeed/cssjs/f58a9.js when it fails. There are no 404’s when the page loads correctly.

The live and staging sites are on the same server and had the same LiteSpeed settings. As I said, the staging and live .htaccess files were identical.

The devices that I am seeing a problem on are:
Safari 13.1.1 on macOS 10.13.6 and 10.15.5
Safari, Chrome and Brave on iOS 13.5.1

I don’t see the problem on:
Non-Apple devices
Chrome or Brave Browser on macOS 10.13.6 and 10.15.5

The child theme contains a few short-codes and a small amount of CSS. No significant changes or overrides.

My environment is:
WordPress 5.4.2
Current Theme: DiviChild
Divi Theme 4.4.8
PHP version 7.3.18

Active Plugins:
AMP Version 1.5.3
Anti-Spam by CleanTalk Version 5.139
Broken Link Checker Version 1.11.13
Easy Table of Contents Version 2.0.11
Forminator Version 1.12.1.1
GDPR Cookie Consent Version 2.2.8
GTmetrix for WordPress Version 0.4.4
LiteSpeed Cache Version 3.2.2
ManageWP – Worker Version 4.9.6
Rank Math SEO Version 1.0.44
SVG Support Version 2.3.18
WPMU DEV Dashboard Version 4.9.2

Server environment:
Server architecture Linux 3.10.0-962.3.2.lve1.5.24.8.el7.x86_64 x86_64
Web server LiteSpeed
PHP version 7.3.18 (Supports 64bit values)
PHP SAPI litespeed
PHP max input variables 10000
PHP time limit 800
PHP memory limit 1024M
Max input time 1500
Upload max filesize 256M
PHP post max size 512M
cURL version 7.62.0 OpenSSL/1.0.2k
Is SUHOSIN installed? No
Is the Imagick library available? No
.htaccess rules Custom rules have been added to your .htaccess file.

The (failing) .htaccess contains:
# BEGIN LSCACHE
## LITESPEED WP CACHE PLUGIN – Do not edit the contents of this block! ##
<IfModule LiteSpeed>
RewriteEngine on
CacheLookup on
RewriteRule .* – [E=Cache-Control:no-autoflush]

### marker CACHE RESOURCE start ###
RewriteRule wp-content/.*/[^/]*(responsive|css|js|dynamic|loader|fonts)\.php – [E=cache-control:max-age=3600]
### marker CACHE RESOURCE end ###

### marker FAVICON start ###
RewriteRule favicon\.ico$ – [E=cache-control:max-age=86400]
### marker FAVICON end ###

### marker WEBP start ###
RewriteCond %{HTTP_ACCEPT} “image/webp” [or]
RewriteCond %{HTTP_USER_AGENT} “Page Speed”
RewriteRule .* – [E=Cache-Control:vary=%{ENV:LSCACHE_VARY_VALUE}+webp]
### marker WEBP end ###

### marker DROPQS start ###
CacheKeyModify -qs:fbclid
CacheKeyModify -qs:gclid
CacheKeyModify -qs:utm*
CacheKeyModify -qs:_ga
### marker DROPQS end ###

</IfModule>
## LITESPEED WP CACHE PLUGIN – Do not edit the contents of this block! ##
# END LSCACHE
# BEGIN NON_LSCACHE
## LITESPEED WP CACHE PLUGIN – Do not edit the contents of this block! ##
### marker BROWSER CACHE start ###
<IfModule mod_expires.c>
ExpiresActive on
ExpiresByType application/pdf A2592000
ExpiresByType image/x-icon A2592000
ExpiresByType image/vnd.microsoft.icon A2592000
ExpiresByType image/svg+xml A2592000

ExpiresByType image/jpg A2592000
ExpiresByType image/jpeg A2592000
ExpiresByType image/png A2592000
ExpiresByType image/gif A2592000
ExpiresByType image/webp A2592000

ExpiresByType video/ogg A2592000
ExpiresByType audio/ogg A2592000
ExpiresByType video/mp4 A2592000
ExpiresByType video/webm A2592000

ExpiresByType text/css A2592000
ExpiresByType text/javascript A2592000
ExpiresByType application/javascript A2592000
ExpiresByType application/x-javascript A2592000

ExpiresByType application/x-font-ttf A2592000
ExpiresByType application/x-font-woff A2592000
ExpiresByType application/font-woff A2592000
ExpiresByType application/font-woff2 A2592000
ExpiresByType application/vnd.ms-fontobject A2592000
ExpiresByType font/ttf A2592000
ExpiresByType font/woff A2592000
ExpiresByType font/woff2 A2592000

</IfModule>
### marker BROWSER CACHE end ###

## LITESPEED WP CACHE PLUGIN – Do not edit the contents of this block! ##
# END NON_LSCACHE

# BEGIN All In One WP Security
#AIOWPS_BLOCK_WP_FILE_ACCESS_START
<Files license.txt>
<IfModule mod_authz_core.c>
Require all denied
</IfModule>
<IfModule !mod_authz_core.c>
Order deny,allow
Deny from all
</IfModule>
</Files>
<Files wp-config-sample.php>
<IfModule mod_authz_core.c>
Require all denied
</IfModule>
<IfModule !mod_authz_core.c>
Order deny,allow
Deny from all
</IfModule>
</Files>
<Files readme.html>
<IfModule mod_authz_core.c>
Require all denied
</IfModule>
<IfModule !mod_authz_core.c>
Order deny,allow
Deny from all
</IfModule>
</Files>
#AIOWPS_BLOCK_WP_FILE_ACCESS_END
#AIOWPS_DEBUG_LOG_BLOCK_HTACCESS_RULES_START
<Files debug.log>
<IfModule mod_authz_core.c>
Require all denied
</IfModule>
<IfModule !mod_authz_core.c>
Order deny,allow
Deny from all
</IfModule>
</Files>
#AIOWPS_DEBUG_LOG_BLOCK_HTACCESS_RULES_END
# END All In One WP Security

# BEGIN WordPress
# The directives (lines) between BEGIN WordPress and END WordPress are
# dynamically generated, and should only be modified via WordPress filters.
# Any changes to the directives between these markers will be overwritten.
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /cm/
RewriteRule ^index\.php$ – [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /cm/index.php [L]
</IfModule>

# END WordPress
# BEGIN wtfdivi

# END wtfdivi

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