iPhone keeps changing to numbers when typing letters

If I type quickly on the screen it will throw in numbers as if I had pressed the 123 button, however the keyboard doesn’t actually change to the numerical keyboard.

I tried turning off slide to type but that didn’t improve it. Also tried rebooting the phone.

Seems like a software issue as it’s not changing the keyboard over, just putting those numbers in. I do notice that the numbers are in the correct position as if the keyboard had changed over to the numerical keyboard.

Any ideas? This is an iPhone 15 Pro Max, fully updated to the latest available iOS version. This problem began recently, in the last week or so. Happens with multiple apps including when I typed this message in Safari. It does not happen when typing slowly.