1. Join populated Conflict server, with multiple groups present on the side you join.
2. Join an existing group.
3. Spawn.
4. I think it is possible that after you've spawned, you will already have automatically switched groups to another. Check the group menu to discern whether this is the case. If so, other group members will see the notification that you've left the group.
5. If you haven't switched groups in when checking in the previous step, respawn.
6. Repeat steps 4 and 5 until you are no longer in the group that you were in before spawning.

This is harder for me to test on my own, as I'm not certain this happens when playing solo. It may require multiple player groups to exist at the time of the respawn. It is uncertain whether this requires a group to be joinable besides the one you are already in (so, unlocked and with space available). Having multiple players working together to test this in one group, in an otherwise populated server, should result in finding the bug very quickly, even without trying.

Even without respawning or without others to help test this, the behavior can be observed in how groups in populated servers will constantly have their members scrambled.

Generally, this behavior makes teamwork with others in the game significantly harder, since groups are used for default radio frequencies and deployed radios. When this is most annoying is when the group was locked, and so it takes extra effort to work around this by rejoining the group.