Here’s an interesting note I found on Leviticus 7.15 in
The IVP Bible Background Commentary: Old Testament:
7:15. difference between thanksgiving offering and other fellowship offerings. Unlike the other fellowship offerings, the thanksgiving offering was often made in places other than the sanctuary. As a result there is a stricter rule about eating it the day of the sacrifice, perhaps to avoid situations where impurity could be contracted. This would not be as big a problem in the sanctuary precincts.
I am not sure if this explanation is even correct, though it appears to make sense at first glance. But, I at least find it interesting that there are different directions for eating the different “well-being” offerings. The thank offering has to be eaten the day of, but the free-will offering and the vow offering can be eaten over the course of a couple of days (see Lev. 7.11-18).
On a different note, I’m not sure whether the fact that I find this interesting reflects the bizarre nature of the things I find interesting, or if it really is as fascinating as I think it is.