Posts unviewable because Permalinks altered

Last week all of the posts on both our WP websites became unviewable because their Permalinks had been altered so that viewers were sent to the 404 Page Not Found message.

For example I just created a post titled Test Post and this is the Permalink that was assigned when I published it.

http://ctgands.org/'/dad738e655c2b2e983e433bca57e6dabd86487ba94f223493dd4abacf4da0684yeardad738e655c2b2e983e433bca57e6dabd86487ba94f223493dd4abacf4da0684/dad738e655c2b2e983e433bca57e6dabd86487ba94f223493dd4abacf4da0684monthnumdad738e655c2b2e983e433bca57e6dabd86487ba94f223493dd4abacf4da0684/dad738e655c2b2e983e433bca57e6dabd86487ba94f223493dd4abacf4da0684daydad738e655c2b2e983e433bca57e6dabd86487ba94f223493dd4abacf4da0684/dad738e655c2b2e983e433bca57e6dabd86487ba94f223493dd4abacf4da0684postnamedad738e655c2b2e983e433bca57e6dabd86487ba94f223493dd4abacf4da0684/'

This is so long that I cannot make my browser window big enough to show the Edit button after the Permalink.

On our other site, adding a Test Post produced the Permalink

http://dev2.ctgands.org/'/2019/01/17/test-post/'/

This was short enough to see the Edit button, but clicking it I could not edit out the single quotes before and after the title part. I do not remember ever seeing such single quotes as part of a Permalink.

This behavior followed our updating to WP5.0 and updating to Theme Twenty Thirteen 2.6-2.7 and Theme Twenty Nineteen 1.1-1.2, but I don’t know if any of those are related to the post Permalink Problem.

Since pages seem to be still behaving as usual, We are converting some 40 posts on our site to pages and writing widgets to display them in the proper locations, but I would like to know if anyone has a clue as to why all the Permalinks became corrupted?