Undefined offset: 0 in functions.php on line 34

this is in /home/vickiyen/public_html/wp-content/plugins/wp-clone-by-wp-academy/lib/functions.php on line 34
what does an Undefined offset: 0 mean?
I have no php skills

This notice came up wnen I backed up this site using wp-clone

Could not get duplicator to work – kept taking too long to create a packeage then the login expires

Started have strange login issues when changed the wp and site addresses a week ago even though I corrected them in the DB. One issue is cannot login with wp-admin, have to logon with wp-login and that doesn’t work on some computers. Can login once in reset your password screen but cannot login normally after that – always have to use to “reset password” screen.
I suspect this all related.

https://wordpress.org/plugins/qtranslate-slug/