I came across this recently where, IIUC, the lowercase was superscript while the uppercase was normal or subscript.
What is this style called?
Regardless of how it is achieved, it is called a "drop cap" or "dropped capital."
Your example without any other context suggests it is a sloppy hack to emulate the effect without having proper control of e.g. baseline offset caused by: ignorance; aesthetic choice; lack of software support; all of the above.
Normally, there would be one drop cap at the start of a paragraph only and usually only one per chapter or section. The fact that there are several in-line suggest an aesthetic choice.