Database error and serialize() errors during change session

Using plugin ver.
Using WordPress ver. 5.4
I recently ran the plugin and had a large number of errors displayed, of two types:
1) Database error
Example:

WordPress database error: [You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 's assumptions about the value of releases https://newurl.com/?p=902";}}' WHER' at line 1]
UPDATE wp_postmeta SET meta_value = 'a:1:{s:7:"twitter";a:1:{i:262062959;s:128:"Releases and Changes: How agile methods have changed ITIL's assumptions about the value of releases https://newurl.com/?p=902";}}' WHERE meta_id = 4923

The value that should have been changed in that record is:
a:1:{s:7:"twitter";a:1:{i:262062959;s:125:"Releases and Changes: How agile methods have changed ITIL's assumptions about the value of releases https://oldurl.com/?p=902";}}

Here is another example of a meta_value field in wp_postmeta that should have been changed, but was not:
a:1:{s:7:"twitter";a:1:{i:262062959;s:135:"Psychology and Service Management: what can we learn in service mgmt from Kahneman's Thinking, Fast and Slow? https://oldurl.com/?p=853";}}

2) Unserialize()
Example:
Notice: unserialize(): Error at offset 4283 of 6738 bytes in /blahblah/wp-content/plugins/velvet-blues-update-urls/velvet-blues-update-urls.php on line 91

There were about 25 errors of this type

The summary screen for the session did not show any information about errors. I would have expected there to be a line stating that ‘x updates failed’ or something of the sort.