Even on the second video, the pilot is heard saying "almost level
attitude" on initial climb out. That is totally wrong technique and
the chute is opening in front of him as a result. That as we saw, is
dangerous.

He would need to climb out a little steeper for the first 100ft and
all would be OK.

Even on winches the chute can open for split second sometimes, but as
the pilot pulls, they close back up again.

Also the climb in the second video is not done very smooth. Proper
technique is to gradually start easing back on the stick and leveling
off as maximum altitude is reached. You will know this because the
sailplane will start rocking back and forth, pitching the nose up and
down, if you don't ease back and the angle remains too steep. The
plane does not like to be dragged through the air at a high angle of
attack, which is what happens when the angle is too steep - regardless
of the airspeed.

Suddenly leveling out and releasing means the maximum altitude was not
reached. Either they leveled off too soon or too late.

Then again, maybe the car had to stop due to a limited ground run.
Then the release technique used in the second video is understandable.
Otherwise not.