I've also this issue , my GF start a game in this map (i was here wwhen she start the map and i've click "stay together") , she see the map but for me it's gone. (so in our case its like a personal bug).

Note i've only this issue on Liferoot Forest (got the bug 3 time in a row but at the begining i think it was working) , so for now its 100% proc chance (in our case).

We play both on PC.

I am also having this bug as are some of the friends I play with. I am not sure if it happens on other maps also though.

On PC, this occurred twice over the weekend, over six instances during one run of Trials/Chaos II.

When it first occurred, I was confused in search of a "Toggle Minimap" shortcut key Or something similar but was dismayed to discover nothing was available.

Additionally on both runs,  it repeated the same Map on a Won run. On the second iterations, the minimap returned. 

i got this problem many times on different maps

I had the same issue, I was on the Liferoot forest map too.

Very often bug for me. Liferoot forest, dead road and forest biome maps dont load minimap. Sometimes when i have played these maps in  this session before - minimap appears.

I see this problem many times on multiple maps. Other players I'm with can see it and I can't or vice versa. 

The dead road does this as well. Usually rejoin 2-3 times before i get a mini map worst has been 10. Mastery seems to be the worst about it for some reason.

PC user

Doing Onslaughts and one of the haunted forest maps had no minimap. Hard enough to solo that on a fresh-out-of-the-campaign character/account, but not being able to see where every enemy is coming from seriously hinders my ability to win a match.

https://steamcommunity.com/sharedfiles/filedetails/?id=1416373850

Happens during the incursion version of Liferoot Forest, too.  If I run this map, it's typically the first map of the day for my daily quest.  Both times I've had an invisible minimap, it was only on the first play through.  The minimap is visible on the 2nd and 3rd plays.

It happens seems to be random to me. The map can dissapear in one wave, and reappear in the next. 

I’ve seen this map bug on other maps as well