Last May (2019) I recorded some clips with just released (at the time) firmware for the V and the footage had a gradual slow tilt into the horizon when stitched with the desktop app. (They had just introduced improved stabilization for the camera). It was a bug with the firmware which Ricoh fixed later.
Unfortunately, the footage was “unsalvageable” for me, unless I was a key framing fool in editing.
Ricoh doesn’t make older versions of desktop apps available(?) Perhaps restitching with an older version of the desktop app could address and confirm that issue with the older footage?