I cannot reproduce the bug. Could you please add these details:
Which version of Polyphone are you using? (this is likely the latest according to your other bug report but just to be sure)
Is the bug appearing only when existing samples and / or instruments are replaced? Or it doesn't matter? I'm trying to find out if the bug is in the replacement of a sample, the replacement of an instrument, or something more general.
I cannot reproduce the bug. Could you please add these details: