Ethercat stuck in safe- OP (sync manager watchdog)

Hello,

we have a communication problem about Ethercat.

When Ctrlx is booting, not all Ethercat slaves change in OP automatically:

Our machine configuration include a S20_EC_BK with 2 encoder modules (S20_INC_2).

We try to replicate the issue using a S20_EC_BK with 2 digital  I/O modules, but the error does not occoure.

In particular this happend only with S20_EC_BK with 2 encoder modules (S20_INC_2).

We noticed the difference between the 2  kind of modules is S20_INC_2 can be included only onboard or on a sercos or an ethercat bus coupler.

Have you got any experience about this situation or do you know why could this happened?

Thanks,

Carlotta.