Text Size Mysteriously Larger in identical Perspective Viewports

There is a block I have been recently altering the text in, and though I have reset a recent version of the block to match a former version, these two versions are displaying differently in two different incrementally-saved versions of the same project.

In Model Space the text displays the same in all views in both projects, but in the more recent version of the project a perspective in a viewport displays the text about ten times bigger than it should, which is ten times bigger than it displays in the same viewport in the previous version. Everything I have checked is identical. The text style and its scaling factor, the “scale” of the perspective views, the scale value assigned to the viewport.

I can work around this by duplicating the text and scaling the version in the perspective, of course, but It’d be better to know what’s causing this and correct it.

It may have something to do with the Viewport, because if I copy the blocks from one project to the other, their display matches one another in both projects.

MOdel space scaling is off in one version and on in the other. Just discovered.