Yes. I have CTCSS set up on the UHF side and when we link to another repeater on the VHF side, there is a PL tone required on xmit.
The problem seems to be with the controller software in the radio. As I said, I can see the receiver go into squelch (the receive LED on the 9100 front panel shuts off). Yet, the transmitter is keyed for an additional 1/2 second after the receiver squelches (the transmit LED on the 9100 front panel remains lit). The transmitter is modulating the PL tone for the entire time it is keyed (as is expected). Thus, the 9100 is actually transmitting a loud burst of modulated noise to the far-end repeater along with the configured PL tone.
For a normal repeater, the controller determines when the PTT signal to the transmitter is active. On our local VHF repeater, the controller uses an output squelch signal from the receiver, plus any configurations for roger-beep, squelch-tail, ID'ing, etc., to determine when to release the input PTT signal to the transmitter. Thus for the 9100 cross-bander, it seems its controller is programmed to blast the far-end with a certain amount of modulated noise at the end of each transmission.
I am hoping there is a setting, firmware update, or hardware mod that will fix this seeming deficiency.