that's bad juju for anything rubber. Most if not all canned/propelled lubricant uses petroleum products as propellant, that mixes in with the silicone oil and can futz up rubber. It even does it on cars, but the rubber products on cars is so thick that it tends to take a lot before it swells noticeably.
50 rounders shouldn't have any issues loading, you shouldn't need to force them.. only a few midcaps with overpowered springs have that issue. The speed loader essentially does the same thing as a push loader it won't make any difference. A speed loader is just more convenient.
If you overlubed your mag, the BBs will be lubed, and the lube gets on the hopup bucking, and depending on how wet it got with the can propellant, it could have swollen, however, if the gun is firing fine with the mag it came with, then it's not swollen and you're good, at that point it's a mag feeding issue.