Rubber plugs bulging out on easy lube

Most likely is grease working its way out. I'd pull the caps and clean out the excess grease. Did you just have them lubed?

Same problem here only my plugs blew all the way out and I had grease all over the wheel. I had repacked them before the trip and blamed it on an air pocket in the grease that expanded when the grease & axle heated. I now check and "burp" them a couple times after greasing and have no more problems...

Did you use the EZ Lube and NOT turn the wheel while doing so?

The rubber plug bulging is not an issue. Mine will do that just from the sun shining on the wheel. But you do need to be sure there isn't too much grease, because that may cause other issues on the inward seal side.

I use my EZ Lubes, but I like to pull the entire hub cover when I do. Then I can better see when the grease is being pushed out of the outer bearing, and I wipe away the excess with my finger, then reinstall the hub cover. You really don't want to fill that hub cover with grease.

The advice above about turning the drum while you pump the grease is spot on as well.

I did pump grease in without turning the wheels when I was away on a trip in 2012, when I was at a Kal tire while friends were getting tires, the owner offered me a grease gun and so pumped in some grease, probably about 12 pumps or so, but the fifth wheel sat since then so it has been more than a year since we used it, and it was a very hot trip coming up to Osoyoos, so I think it might be the heat, did buy a little pump from a home hardware and some little grease tubes just in case it needs grease.
Thanks for the replys.

Be very careful if you decide to clean up the excess grease. If you run your fingers around the metal edge it can be extremely sharp. I know from experience. Use a rag and be careful your hand doesn't come in contact with the edge.

As mentioned, I turned the wheel while greasing and still got air.
It seems like grease of different kinds will be used in the EZYlube. I don't know if it matters anymore but the conventional wisdom was not to mix types of lube. Not knowing what kind of grease the previous boat owner used on the trailer I pulled all wheels, cleaned off all grease, and repacked with "my" type.... FWIW..