Reloading a regular texture will convert it to a virtual texture if the size is greater or equal to the "Auto Virtual Texturing Size" setting.
This is often not the desired behavior. The status of the texture shouldn't change on a reload.
If we want to change the status we can use the "Convert to virtual texture" tool.
Note also that the status never changes from virtual texture to regular texture based on the "Auto Virtual Texturing Size" setting.
Use a project that has "Enable virtual texture support" checked in the project settings.
Set the "Auto Virtual Texturing Size" to something large such as 8192
Create a new texture of size less than 8192 (2048 is a good choice).
Note that it is a regular texture (no VT text in the thumbnail).
Now set the "Auto Virtual Texturing Size" to the same or smaller than your new texture size.
In the texture asset context menu select AssetActions/Reload.
After the reload note that the texture is now a virtual texture (with the VT text in the thumbnail).
There's no existing public thread on this issue, so head over to AnswerHub just mention UE-109306 in the post.