Skim 1.5.4 (120)
MacOS 10.15.4 (19E287)
Since updating to Catalina and Skim 1.5.4, I can no longer select and highlight text in some vertical-text Japanese documents scanned and OCRed before the updates. Attempting to select any text on the page selects the whole page as if it had not been OCRed. This was not a problem before the updates, which I did simultaneously. I can still search the documents just fine, but even then the search term is not highlighted on the page. Old highlights are not deleted. AFAIK, this is only affecting OCRed vertical text.
Screenshot attached.
Text selection is done by Apple's PDFKit. We cannot change this, we don't
have access to the underlying text other than what PDFKit gives us. So this
is a problem only Apple can fix.