MC34FS Module Dropout On Update

We have a system with 1 x MC43FS, 1 x MD4-7, 1 x XC21 and 2 x MC41FS, running 6.08.30.8216.

On MC43FS we have 2 x CAN Open encoders on CAN Bus E that are sending PDO and heartbeat information as soon as we apply power. These are configured to run at 125kbps. We established that when updating the project it would update all the modules except MC43FS which hangs and crashes out. It seems to begin updating the MC43FS module (does it last in line after all the others), but stops halfway through and crashes out. System has to have power cycled and screen says no application and have to reload the software. Occasionally it will load in, around 10% success rate. When it drops out i get flash 'no application available' as in instruction manual.

Unplugging one encoder and IQAN will allow me to update the system including the MC43FS with occasional dropout.

Changing the bus speed of the encoders has improved it, seems to allow me to update the system with both encoders connected smoothly, occasionally hangs but significantly better.

Is there an interaction between the MC43FS firmware and speed of CAN devices? We had this issue a few years back on a MC3 and that was conflicting speeds on firmware check before boot. Seems it may also be present on these newer modules?

Weirdly also it says 6.08.24 for the MC43FS, however we are using 6.08.30. I noticed the IQANDesign 6.08.30 only has this for the MD4 and not the MC43FS, which mislead me somewhat when trying to establish the fault.