There's no "issue with the SD", there's an issue with people not understanding what Google did.
Up to 4.3, any app could read from or write to any folder on the SD card - it was just an external data dump. That's not just bad security, it's no security. Put your password program's data file on the SD card and any virus can steal all your passwords. A badly written app can write a file to another app's folder that's using the same file name for
its data - wiping out the second app's data.
Since 4.4, the SD card is part of the Linux file system that Android runs on. An app needs Linux permission to read from or write to a folder - on the SD card now, the same way it always did in the /data folder tree in internal storage. An app that's properly written (see: "hen's teeth" - most "Android app developers" aren't software developers, and the concept of "you can't do just one thing" is something they never heard of) will allow you to set its data storage location to a yet-to-be-created folder on the SD card. It will then create the folder and be able to use it with no problem. If the app you're using can't do that, it probably has other problems as well. (If the folder already exists, rename it using your computer [which doesn't know about Linux permissions], create the folder with the app, then move all the current files from the renamed folder to the new one [using the computer again] and delete the renamed folder.)
Or, if you don't care about security, corrupted or lost data, etc., run
NextApp SDFix: KitKat Writable MicroSD (root) (the phone has to be rooted because only root has unconditional access to all folders) and you can use the phone like 4.3 did - anything can write anywhere on the SD card..