There was a very similar post, where character was climbing something, at the end of the climb it was a fraction of a pixel lower than the floor level, which caused it to bounce up and jumping/falling animation was triggered for a very short time.
It may be something similar in your case - character is either a bit higher or a bit lower than the floor at the end of the climb.
You can add some debug output (Browser->Log) to your events to check Player1 coordinates at the end of the climb, at the beginning and end of falling/jumping animation etc. This should tell you what's going on.
Or you can simply add a short cool-off time after the climb, something like 0.2s, during which ignore jumping/falling events.