Rick, polyphony is for real..It can be a big problem..
Each manufacturer has a different way to handle it[priority]..
I have always preferred Roland's design..besides last note priority, certain channels have priority...the drums and bass are one, two on the list.
Some Roland gear , you can select your priority..but in all the models you are assured the bass and drums will not drop out, followed by the main voice[s]..

If you really need to test "Big Time"..Play a SMF[standard midi file] on your keyboard, and layer strings and piano, using your hold pedal play over the top of the SMF.

32 polyphony is terrible in this scenario.
On some brands 126 polyphony[hint] is bad.

The more forgiven brands are Roland and Korg..

My experiences with PSR's[early 32 voice polyphony]..they would mute everything for a few seconds when they drop out..

The Casio 32 voice are also noticeable with dropouts, although they do not mute the board entirely..

The last not priority design on the 62 voice Korgs handle the drop outs better than the 126 voice Yamaha's..and the Roland 64 voice[G1000] handles this even better than the Korg..

Maybe, drop outs do not bother you in your style of play, but if you listen you will hear the sounds dropping out...it is for real..