Bug when opening pdf with reader on android

When I try to open any pdf file downloaded from my browser (Chrome or Firefox) it does not open successfully in any viewer. For example opening it with Adobe Acrobat Reader (4.5) I get the error: "This file cannot be accessed. Check your connection or make the filename shorter." At some point in the past this was working correctly. (Note the actual filename length does not seem to matter. The issue occurs for files with short names.) Weirder yet, I can open the same file when selecting Open with Adobe Acrobat reader for the exact same file through my file browser Total Commander instead of through chrome. The downloaded file is clearly not actually corrupted in anyway. --- Android 10 on moto g(9) plus