Effect Loop on X slot still coloured by cab sim

I´m using a "mono loop" locked on the "X" slot with some external effects and a Roland RC-20 phrase recorder.
Sounds perfect through direct out and headphones.
On monitor output sounds great until I record something on the RC-20 and then change the rig. The sound reproduced by the RC-20 is coloured by the cab simulation of the new rig (even when it seems to be AFTER it on the chain and cab sim is of for monitor output at Master section).

Any thoughts?

Axel

Nope, cab sim isn´t locked. I´ve notice that even with cab sim off for monitor out (from master section), when I turn it off from front panel the sound still change (cab sim like). The noise or coloration is only heard when the phrase recorder is playing while I change rigs (more noticeable on high gain types).