There are a group of countries that consistently have no problems with an Israeli stamp (Jordan, Turkey, Egypt, etc.), then there are those that consistently deny entry (Syria, Lebanon, Iran, etc.), then, as I mentioned on your other post reference Bahrain, there are a few countries which generally have no problems with an Israeli stamp, but can, depending upon the immigration official on duty, inconsistenly deny entry. This doesn't happen very often, but can happen. Oman falls into that last catagory.
There's nothing you can do about it and it's unlikely you'll encounter a problem. You can't control Middle East politics so just relax and take your trip.