Not saying that this match was match fixed but you should really do some research. People will and do match-fix literally anything and everything they can when it comes to sports, especially in some eastern countries. Was watching this podcast a couple months ago with Richard Lewis and Declan Hill, this well know academic/journalist that's worked cases and written books on the subject and is considered the world's foremost expert on match-fixing in sports. He mentioned he's seen match-fixers even fixing soccer matches between like random teams of 13/14 year old children and that as time passed we would inevitably see it more and more in esports. which we kind of already have. Been plenty of it in CSGO and not too long ago we saw china's LDL(secondary league of legends pro league) shutdown temporarily to investigate some match-fixing that had been taking place.
Once again, not saying that the immortal/EG match was an example of this(I highly doubt it was actually). But yea, it's definitely always a possibility. And more so with those competing at lower levels as they're the ones more in need and likely to be willing to fix for $$$.