Applied effects missing from FX edit window

I am using Premiere Elements version 19.0 (20210127.daily.2235820) on a PC running Windows 10 Pro 20H2.

I spent a considerable amount of time editing a video, masking out various faces using a combination of track matte and the mosaic effect on a video layer containing a shape object.

I had no problem during the initial edit, but when I go back in to make changes,several days later, although the effects are present on playback, the mosaic effect no longer shows up in the "Edit FX" panel, all I see is Motion and Opacity.

In addition, when I go to create a new text layer with a shape, apply the mosaic effect and track matte, the effect does not actually get applied to the output video, at least in preview.

Any suggestions as to what I can do to fix this issue?