I think that these guys are injecting way too much gear. Too much oil in the muscle. Not SEO, just carrier oils for test and other anabolics.
Back in the day -- and I mean the 70s through the 90s -- orals were way more popular, test was far less popular, and total injection volumes, even for pros, were like an order of magnitude less than they are today.
High-volume injections can lead to nerve damage, muscle necrosis, and watery swellings. Rami, Nick Walker, and Hunter Labrada are like the poster boys for this.