This is from the manual. So it appears that the Firmware should have not been downgraded. Sometimes Firmware and memory can be corrupted when loaded or just during use so doing a new Firmware install will not hurt anything and may straighten things. I hesitated to comment because I don’t have any experience with the H90 so I don’t know all the ins and outs. I can say that the H90 is a different beast than the H9 with a lot more going on. Sometimes bugs take a bit of time to flesh out. I know it’s frustrating and if it persists definitely contact Eventide support. These devices are very dependent on source code and just a few code tweaks and new firmware that will get things running smooth. Hopefully an Eventide staff person will chime in with some better information.
”D.3. Factory Reset
Press and hold all three Quick Knobs while inserting the power cable until the text “Performing factory reset” appears on the H90’s screen.
A Factory Reset will erase all User Lists, Programs, and Presets. This will also reset the System and Tempo settings. This will not downgrade the firmware.”