I was playing a bot match, as Dynamo. During the game, I have encountered a short period of severe lag, which appeared to be Network related - character animations not playing, menus not showing on button press but after a delay, jumpy motion etc. It was accompanied by audio bugs as well - music and SFX breaking up. A couple minutes after, I encountered a similar lag period, however, this time the game froze up - and after a while went full Not Responding on me. I force quit using Task Manager. The lag seemed to pop up during moments of intense action - lots of characers and abilities flying around. While I am running lower-end hardware (1050Ti, old i5, 16gb RAM) I do not believe that the graphical intensity of the scene was related to the crash, though it might have contributed to the lag.
No screenshots or anything on this one, sorry.