I’ve seen this mentioned in the ‘known issues’, and som bug-reports as well… can anyone provide any additional details? I encountered something similar in a recent Great Rift, and it seemed - to me - to be a highly specific and easily fixable issue. However, the ‘known’ version has been mentioned to be caused by ‘certain playstyles’ or whatnot, which doesn’t sound like what I encountered, so… I’m basically not sure whether to report it, or shrug it off as a known issue.
What happened, as far as I could tell, was that one of the ghost-type enemies - you know, the ones that periodically turn invulnerable and intangible in order to dash through the scenery and out of your line of fire - was doing exactly that at the moment the Rift Boss appeared. Hence, whatever ‘instadeath’ effect this appearance has on rift enemies failed to affect him (it?) and also got him stuck in ‘intangible mode’. After taking out the boss, that ghost just continued to dash around, untouchable, bugging me. Fortunately, its habit of periodically running away enabled me to Town Portal home without too much trouble - I even returned (overloaded with Blood Shards, ya know, couldn’t pick up everything the boss dropped) and ascertained that it was STILL darting around.
Is that the ‘known issue’, or something different?