I have similar concerns about an O.S. 46AX engine I recently started breaking in, worried I may have run it too lean. Meaning not enough oil. Might be similar to your case I guess, even though this is a methanol engine running on 18% oil.

According to the instruction manual, the symptoms can then be that the engine drops in RPM when it gets hot, because it is still too "tight" (not finished breaking in). The instructions said to then run the engine rich on the next flight instead. Based on this, I would guess there's a chance the engine will be fine, it just isn't finished broken in yet. So maybe it would be good to re-do some of the break in runs with the higher oil mixture. But I'm no expert and don't have any other experience with this, just mentioning it in case it's relevant.