You do have to hard reset. If you're using Gambatte you should be able to bind a key to hard reset.

Are the reset inputs the same (Up + Select + B, Start, A)?

I've tried resaving, new save states, new runs, everything. Always the same Zubat on the same tile. There has to be an incredibly specific error all of us are making.

Encountered this issue myself and started researching hard (explains what I'm doing on a 2 month old post) and made a post myself about it. I've found Youtube comments and forum posts explaining the exact same issue, a level 9 Zubat 5 tiles down from the ladder. I have found no answers. The usual reply is to make sure you're buffering right on the moon stone but I know I am. I feel like for this many people to have the same specific problem means there's a very specific thing we're doing wrong, but so far I've found nothing. If anyone out there knows, please help.

Just did some digging and figured out that I somehow missed the Super Nerd on the save state I was practicing on, which results in a level 9 Zubat appearing 5 tiles after the Moon Stone. Thanks for your help!

I've resaved a couple times to no avail, so I'll try to work on the Moon Stone timing. Thanks.

Currently working on my Paras manip in Mt. Moon, but it's not going very well. I would just chalk it up to a lack of experience but I'm getting the same outcome every time. After the moonstone, I go down the ladder, walk 5 (I'm pretty sure) tiles and get an encounter, a level 9 Zubat. Every time. What am I doing wrong?