I'm PC only and have no experience with MACs. This situation normally occurs with me when I've imported guitar audio. In most cases, it's most beneficial for me to convert the stereo guitar to a mono signal anyway and almost always I use panning with multiple guitars in a project so I thought I'd post in the event the original poster's project could be completed with the work around rather than wait on an update if it's in fact a bug.

There may be a simpler fix but this is how I've always addressed it. It would not surprise me to learn of a setting somewhere down in the menus to be checked or unchecked.

BIAB 2025:RB 2025, Latest builds: Dell Optiplex 7040 Desktop; Windows-10-64 bit, Intel Core i7-6700 3.4GHz CPU and 16 GB Ram Memory.