File name too long - docker

I have a latest urbackup docker container running on a Synology NAS.

However, it often fails with File name too long.
Directly after installation I quickly saw a message about it having problems with the maximum path length, but I couldn’t find a setting for it to even try out different length.

Errors 12/06/20 19:59 Error getting complete file “kwud1TKRMzAbxvK06Ygu|C/Program Files (x86)/Steam/depotcache/1151342_4143008098003073231.manifest” from luckydonald-PC. Errorcode: BASE_DIR_LOST (7)
Errors 12/06/20 19:59 Client luckydonald-PC went offline.
Errors 12/06/20 20:14 Renaming file “/backups/luckydonald-PC/201206-1749/.b68xO+K9SCOF35cLk4Bf9Q/59727” to “/backups/luckydonald-PC/201206-1749/C/Program Files/UrBackup/tokens/group_6e74207461736b5c6d6963726f736f66742d77696e646f77732d736f66747761726570726f74656374696f6e706c6174666f726d2d737663726573746172747461736b6e6574776f726b” failed -4. File name too long (code: 36)
Errors 12/06/20 20:14 Storing file to “/backups/luckydonald-PC/201206-1749/C/Program Files/UrBackup/tokens/group_6e74207461736b5c6d6963726f736f66742d77696e646f77732d736f66747761726570726f74656374696f6e706c6174666f726d2d737663726573746172747461736b6e6574776f726b” failed
Errors 12/06/20 21:23 FATAL: Backup failed because of disk problems (see previous messages)
Errors 12/06/20 21:23 Backup failed