As visible on your screenshot the two masters are not set up the same and also cannot, as in the ifm sub-devices can be plugged in and in the SR no sub nodes are existing. The second behaviour looks like known feature that is currently not supported by ctrlX CORE. When adding a "sub master" like such an EtherCat to IO-Link converter it would create another master node in the Engineering that needs to be configured separately. This is currently not possible in the ctrlX CORE.
Please have a look to the list of tested devices "3rd party EtherCAT slave interoperability list".
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