MG T-ABC

I've just finished sand blasting a front axle and found some oddities. For one, there is a bunch of filler material under the paint. The filler came out of one part in a big lump and feels sort of plastic-like. The filler in other areas of the axle seems a bit different, almost like metal. Did the factory ever do this sort of thing to correct casting flaws, or is this just a previous owner covering up damage or flaws? I'm a bit concerned at how deep the one on the end of the axle is.

Also, someone has relieved the axle around the front four standoffs. I haven't noticed this on other axles but I wasn't looking for it either. Has anyone else seen this? Or maybe the previous owner did this to accommodate incorrect sized hardware?

Pic 3 almost looks like an old crack repair. Probably not? Maybe just some rust chewed on it. Interesting grinding someone did.