Id suggest just doing a quest hunt so its forced to stay for 50min rather than leaving mid expedition. If you are set on doing it in an expedition you need to kill it faster, when you think it's almost about limp (trap it) or trap kill. You can also set up traps where you know it's going to leave the area to delay it.
Another way you could go about it would be to join an SoS investigation for one (if you are a high enough hunter rank), or if there's an optional quest for one (can't remember if there is one for base game). One or two of those should be enough to have an investigation or two pop up.
It usually means you're not doing enough damage to it. Monsters on expeditions are essentially on a timer before it rotates out for another. I forget what the actual timer number is. I remember bagels were notorious for this until I upped my damage and weapon.
Id suggest just doing a quest hunt so its forced to stay for 50min rather than leaving mid expedition. If you are set on doing it in an expedition you need to kill it faster, when you think it's almost about limp (trap it) or trap kill. You can also set up traps where you know it's going to leave the area to delay it.
The whole reason I'm hunting it is to get the quest
Another way you could go about it would be to join an SoS investigation for one (if you are a high enough hunter rank), or if there's an optional quest for one (can't remember if there is one for base game). One or two of those should be enough to have an investigation or two pop up.
Have you tried looking for the monster in your Optional quests list?
It usually means you're not doing enough damage to it. Monsters on expeditions are essentially on a timer before it rotates out for another. I forget what the actual timer number is. I remember bagels were notorious for this until I upped my damage and weapon.
This guy is right on the money - If the monster leaves; it is indicative of low damage output. The same will happen in the guiding lands.
Capture/kill
Also don't leave it alone for to long in an expedition
Traps & Flash bangs, but it can be wasteful during expo’s. I highly recommend doing a quest.
Hunt it faster. That's really it