Well... in a real scenario anything can happen, there's lots of variables to account for.
Were you jumped right after you got the info from the drone or a while later?
Maybe another squad was chasing your squad for some time, but kept a distance until then?
Maybe they used some sort of teleport like wraith portal or Ash portal?
Maybe when you used the drone, they were on the edge of the scan-zone, and right after you pulled the drone out and got the info, they started chasing your squad and you sat in the building/cover, thinking you were safe but then got jumped?
It's hard to account for all of these possibilities without a replay of the match, but currently, we don't have anything like that... So testing in practice range and providing video evidence of bug reproduction is the only way for sth like this...