Hi Hunter,
It’s a well-known feature, and I have a couple workarounds to make log acceptable for OPUS.
First one, you can record the UBX log along with the RINEX. Then, Emlid Studio joins the game: it’s possible to convert the UBX log into the RINEX with the Time rounding option as shown in the screenshot below:
It adjusts RINEX epochs on integer values.
Second one, there’s time rounding by default in RINEX logging in our latest beta firmware version. You can enable Beta updates in the Firmware updates tab.
UPD: fixed some wording