I noticed when using the br 155 for the 6:15am DB80301 service which is Finnentrop to Letmathe PZB works as it it should but when driving the service after with the br155 which is the 7:00am DB80302 - Letmathe To Finnentrop I shut down the cab I used for the first run and then changed cab for the run back and upon passing either a speed reduction or a expect stop signal aspect I acknowledge it with PZB by interacting with the PZB acknowledge lever in the cab and it doesn’t do anything and a PZB emergency brake application occurs as if I didn’t acknowledge anything.
There are some PZB-acknowledge bugs about the 155. Curiously, same services works with 185 and 143. https://forums.dovetailgames.com/threads/paradox-a-game-so-good-it-is-bad.27110/
Remember, these issues "don't stop you playing the game" so I doubt they'll rush to sort them. But we can always be hopeful