Im unsure what additional information to provide that would help but I will simply explain my setup.
I Downloaded the Server pack for BMC 4 from curseforge.
Ensured it ran normally.
I added PCF 1.2.2 which crashed with the following log
latest.log
I downgraded to 1.2.1 and the server launched and works as expected.
If it works, it works but a bug is a bug. Hope this helps!