Generated Collection Posters not Displaying When Selected

The 4 part collection posters that are auto generated have stopped being displayed for any new collections I add. This effects both movie and show collections. In the collection under settings:poster the auto generated poster will display correctly (see pics). However, selecting it will only display the poster of one of the collection items (usually the first collection item I added). Older collections will display the auto generated poster but will not update the poster if new items are added. It was working perfectly up-until a week ago. Any other poster I select for the collection will display as expected. Downloading a poster from URL will also work. However selecting the auto generated poster will only result in a single item poster being displayed. I have deleted collections and tried recreating them with no positive effect. I have cleaned the bundles. I have optimized the database. I am not sure how to proceed. I am not seeing much info related to this issue here in the forums. Any help would be appreciated.

Server Version #: 1.26.0.5715
Server: Synology DSM 7.0.1-42218 Update 3
Player Version#: Various Client (up-to-date)

Hi, I had the same problem with the same software-versions like you.
I updated to the latest DSM (7.1-42661 Update 1) and the latest Plex-Server Version #: 1.26.1.5772-7000 and now it works fine.

You were correct. Thanks.

I installed PMS 1.26.1.5772 and the collections poster art problem is gone. This must have been a bug with the public release of 1.26.0.5715 which is about when I first noticed the issue. I left my DSM at 7.0.1 so it appears the DSM version does not have anything to do with this issue.