How to use filter in collabora online?

I have a problem that shown big space at the top as below picture when use filtering in Collabora Online.
But nothing problem when open the same file on Libre Office.

If possible, could you please tell me please…

I am currently on:
Nextcloud ver: Hub 4 (26.0.13)
COOLWSD version:

■Test Environments
OS (Ubuntu, Windows10)
Browsers(Chrome, Vavaldi, Firefox)

I don’t see the issue here.

with NC 28.0.3 and dedicated CODE I would first start updating to the current versions NC26 reaches EOL in few days. hopefully it helps already, if not start checking for special conditions. start with “common” scenario: easy table with latin/ASCI characters and add complexity step by step.

you screenshot looks like the top row contains multiple cells… pls double check your data if it contains something weird e.g. line brakes, merged cells: