I've found that sending 2 values with a single parameter command sets the morph value. When I send the same value twice it 'removes' the morph and solves the problem. I think the morph function messes with this setting. So now I just send:
F0 00 20 33 02 7F 01 00 3C 45 39 50 39 50 F7
For now, it seems fixed ? But not for the reverbs, only the delays. The reverbs kept on doing this thing... I now just send a normal CC after the NRPN setting the mix and decay. But it's weird right?