Thank you for the bug report! I tried replicating it (starting from a fresh save) but couldn't find the described issue. I need more details:
1) did you get the cutscene that triggers right in front of the gate? DO you have the hill key in the inventory?
2) is the gate collision blocking Maya, or can she run all the way tot he right?
3) Had you unlocked this gate before, or did you just get the key from the Beach Boss and then returned here?
4) When you press the interaction button where the gate should be, do you get a dialogue from Maya about the locked gate?
5) If you can, posting a screenshot of the area would also help a lot!
I actually managed to fix my problem by trying one of the things you suggested(interacting where the gate should be, which tbh I probably should have tried before). I'll still let you know what happened in case you want to try fixing this issue.
1. I did get the cutscene guiding me back initially. I do have the hill valley key in my inventory as well.
2: Maya is able to run all the way to the end of the screen, but is unable to move to the next area.
3. I never got to unlock the gate, I defeated the Beach Boss and returned to the gate where I found it missing.
4. When I reached the gate, or where it should be, I was able to interact with it and resolve the issue thankfully.
5. I can't seem to upload screenshots unfortunately.