Weird edit box behavior

I’m having an odd behavior on my edit window on my phone.

Normally when I select Reply, the window opens at the bottom of the screen, and then when I select the box to pull up the keyboard, the small window expands to fill the top half of the screen.

For a while now, the small edit window has been jumping to the top of the screen, but not expanding.

It stays stuck until I close my browser and reopen it.

I typically use Samsung Internet. I’m on Samsung Galaxy 21S. It’s not the newest, but it’s still good and hasn’t had this problem until recently.

Any ideas?