B737 MAX 8 Flight Attendant reported that upon arrival; a girt bar was not in the brackets after disarmed door was opened. Captain was notified and confirmed the escape slide did not deploy.

Narrative

Upon arrival into ZZZ; I performed monitor and challenge at the forward entry door. I both verbally and physically cross checked FA A. Both doors were fully disarmed. I gave the agent the thumbs up and as she opened the door; FA A and myself noticed the girt bar popped out on the left side of the bracket holder. I told the agent to stop opening the door and to check the bottom for a possible inadvertent slide deployment. Luckily; there was no slide deployment but the girt bar was not in the brackets. I notified the captain and we began deplaning. The captain inspected the girt bar and slide and confirmed it was not a slide deployment. He put the girt bar back into the bracket. After deplaning; I performed my final cabin walk through and double checked the girt bar was in the correct position. Suggestions: This occurred on a newer 737-MAX. All procedures were performed as usual yet this girt bar still popped out when the agent opened the door. I believe the girt bar popping out was due to mechanical reasons. I have never had this issue on the 737 and when it comes to procedures I am very focused and alert.