eBUS Adapter Shield V5: After update sending data to the eBus not possible

[HerbertKoeln]

Hello,
I use the eBUS Adapter Shield v5 with firmware build: [20240106] with a self-created eBus class in c++. Everything (read/write) works fine.
However, when I try to update to the latest firmware, writing to the eBus is not possible. Debugging the traffic shows me that the adapter is not sending data to the Ebus. It seems to me that there is write protection.
Question: Are there any known changes to the extended protocol (not yet documented) that can be used to remove write protection?

Thanks for help!