Media Management - Series folder format

[ChrisVrolijk]

Sonarr version (exact version): 3.0.6.1342
Mono version (if Sonarr is not running on Windows): 5.20.1.34
OS: 3.0.6.1342-ls127 by linuxserver.io

In some occasions my series folder does not include a year.
Is this a misconfiguration on my side or an other issue?

My setting looks like this

[markus101]

Any series added before that setting was changed would fall under the previous value (as shown as the path for the series).