I can see this is still an issue in the latest release.
Having watched some recent youtube videos on MSFS Trim, I can see the same issue in the videos, it seems to go unnoticed by others. The Trim button is pressed and held, there’s an initial tiny trim input then a pause and then a continuous input.
The control setup in MSFS has an input type “On Press” or “On Release”. On Press should mean “On Press”. at the moment it’s “On Press then a little pause after Press”.
Perhaps add a ‘Continuous’ option here, so an input is immediate and continuous on press.
…Or change the “On Press” option to read “On Press but with a little pause after Press”, because that’s what it actually is doing. It’s a bug, it should not be doing this for Trim input (trim buttons IRL are immediate and continuous, as modeled in every other flight sim in the past 20 years. ).