Steps to reproduce:
1. Open the “Project” project in any but standalone platform
2. Select one of the textures in Assets/PlaceholderUI
3. In the Inspector window change any property
4. Press the “Revert” button
5. Observe the selected texture .meta file
6. Close the project
7. Compare selected texture .meta files before and after closing the Editor

Expected result: No changes to the metadata file
Actual result: Module settings are added to the metadata file and only when the Editor is closed

Reproducible with: 2020.3.42f1, 2021.3.15f1, 2022.1.24f1, 2022.2.0f1, 2023.1.0a22

Reproduced on: macOS Monterey 12.2 (Intel)

_+Clarification regarding this case+_: https://unity.slack.com/archives/C0105CH72UV/p1676629311940149?thread_ts=1670943038.241429&cid=C0105CH72UV
(In short: not specific to texture platform settings or the TextureImporter. When viewing, for example, a texture with no Android platform settings when the Android platform support module is installed, it is expected that Android platform settings are created "in the background" -- this is to help with Presets support. Only viewing/scrolling through the platform settings does not cause these "background" platform settings to get saved to the .meta file (even after the editor is closed). Editing ANY importer setting then pressing "Revert" and closing the Editor however does, strangely enough, update the .meta file, even though you would expect that "nothing changed". It looks like this is because the "m_DirtyIndex" is non-0 (a change occurred), when we would have expected it to be 0 (no change). Any property may appear/disappear/change and cause noise, depending on the age of the .meta file (example: "serializedVersion" or the platform settings mentioned in this bug). This is not limited to the TextureImporter and seems to happen with, at least, all importers that have the "Revert" button -> see comments for repro steps with "RevertBug_WithAudioImporter.zip")