The bug
This is a similar problem as the namesake, MCPE-18376. When typing or removing text inside the Creative mode search tab, the text can be slow to change or update, especially when there's a lot of it, and more so if text is modified towards the start of the search query.
What I expected:
For my changes to the text inside the search query to not cause such a delay.
What happens:
There is a noticeable delay with adding/removing characters.
Reproduction steps:
Open the Creative inventory, and navigate to the All tab to use the search function.
Type some text in the search box, it can be anything really. The longer your query is the easier this is to reproduce.
Go back towards the start of your search query and try to remove or add some characters. Note the delay.
I don't have video evidence, as my device doesn't handle nor support recording video well.
Verified from me as well. iPad Pro 12.9” Gen 1 on iPadOS 13.4 with Minecraft 1.14.30.
I filled the textbox to capacity then went to the first few parts and tried to delete characters and found it extremely slow to respond. Typing was the same. Tested on multiple different worlds too all the same.