89 xj Leaking freeze plugs ODD

So i just put a 94 H.O. in my 89 I got the engine from a wrecked donor. When doing the swap i put all new everything including brass freeze plugs. i got them out while it was on the stand making sure not to hit the plug recess and to actually hit the plug. Once they were all out i hit all of the block recesses with steel wool and 320 grit sand paper. When installing the nee brass ones i coated the edges in shellac head gasket sealer and taped them in with a socket and extension making sure all were straight and perfectly seated aginst the chamfer all the way around. I even had to redo some i wasnt happy with.

At first they sealed perfectly and everything was fine ive taken it wheeling twice, driving it to and from the trail, with no problems until yesterday i noticed the first two are weeping down the side of the block. Its not bad, not enough to make a difference in the water level, but i have no water gauge right now so im really treading on thin ice right now.

Any ideas on what could cause this?
How could i drive 2000 miles them be fine and now have a problem?
Did i overheat it and that cause it?
Improper installation?

The stock sending unit for the gauge was broken off in the motor and i failed to notice until i already had it in. I shoot it with an IR thermometer every hour of driving or so and ive never seen anything over 210 at the tstat housing.

Sounds like you installed them correctly. Brass and iron have different rates of contraction/expansion, which is probably why they're weeping. Leaks like these usually resolve themselves, so I'd leave them alone for awhile and see if they stop weeping...