Hi!
This occurs under both 1.4.993 (Preview) and the most recent (e8eaee106966d0bb9829ea3eea32bb98019) daily of 1.4.999. My testing has been under MacOS with these versions, but this consistently happens in Windows as well (where I run the 1.3 stables).
In both builds, when using the mouse scroll wheel to browse through a document with embedded {gt} chunks, as soon as the mouse pointer hits the same vertical space as the embedded object, scrolling no longer works and focus has to be manually moved to another part of the document for wheel scrolling to work again. Since there is a lot of space padded to even small inline {gt} objects (another gripe for another day), regaining focus requires using the vertical scroll bar, document outline (if present) or keyboard navigation. Super annoying when trying to quickly browse through a document. 