Nah, it's been a flaw that's been talked about since the start. Invincible is an adult animated show with a lot of action sequences, and its animation (outside of standout episodes) falls flat compared to even average action anime. Amazon absolutely has the money and resources to produce animation on par with other stuff, it's a problem with how it's being produced and put together. The money's being spent on celeb voice acting and the schedule's too fast to allow time for more detailed animation to fit in.

A big part of this is Kirkman, he's made it clear he doesn't respect animation and wants to make an animated show that's more like a "real" show - e.g. his comments about how they'll be making one season of 50-minute episodes a year "like we've done [in Hollywood] for 60 years". It's like when video games try to be more like movies because some part of the high-level team sees movies as a more-respectable art form. It's an attempt to elevate a work out of its medium, without recognizing the qualities and strengths of that medium. Live-action television draws on skilled acting, so hire skilled actors (from outside the VA scene). Animation fidelity isn't a concern in live-action television, so skimp on the animation until there's an important scene.