I've noticed that it's sometimes impossible to get text to fade on a clip. I applied the fade after adding the text, and sometimes, it won't fade at all. In my case, I have a clip that will only fade in or out, but not both. When I apply the filters, the text will fade in, but it will not fade out. If I drag the end of the clip to make it longer or shorter, it will then fade out properly, but it won't fade in at the beginning anymore.
This is pretty common in v17.12.03 on Windows, and I've seen it in earlier versions, too. As a workaround, I think I'm going to have to split the clip into 2 parts, one for fading in, and one for fading out. It's pretty reproducible for me.