BlackBerry Forums Support Community - Media card encryption problem

I've been using the option of media card encryption for a few months. I like to know that my pictures are protected in case my BlackBerry gets lost or stolen. However, I've been too close to losing my content, more than once. Every now and then, my BlackBerry just won't recognize the encrypted files anymore. It fails to decrypt them for some reason I cannot determine. The last time it happened, it seemed to be connected with removing the media card, but I am not sure. Here is how it happened:

I got a new media card, bigger capacity. So I removed it from the BlackBerry, put it in a USB adapter and copied everything over to my PC.

Note that I use Linux, so my PC cannot read the encrypted files. I just copy everything over to keep the copy, and most of the files are not encrypted anyway. I am not going to waste my time cherry-picking the unencrypted ones, I just copy everything over. The encrypted ones I backup by sending them to myself over email. They reach my mailbox on my PC unencryted. Backing up files over email is slow and annoying, but hey, it's a BlackBerry, which is far from perfect... The encrypted ones are not many anyway, just pictures and occasional voice notes.

Fine. Then I put the new card in the USB adapter and copied everything over from the PC to the new media card. However, the new card is twice as large, I still didn't know for sure what I was going to add, so I didn't put the new card in the BlackBerry yet. I was in a hurry to go out, so I just put in the old card and went out.

I soon realized that the BlackBerry could no longer recognize any of the old encrypted files. I had one video, about a dozen pictures and a few voice recordings made with VR+. All the pictures had been backed up already, the video and the voice notes hadn't. I thought I had lost them. I went ahead and took pictures and new voice notes. The new content worked fine, the old content was still there, but the BlackBerry could not read it. I am not talking about the files that had been copied to my PC then copied to the new media card. It's still the OLD media card. I just copied a bunch of folders from it over to my PC, I didn't change anything in it.

Today, I finally decided to use the new media card. After sending all the pictures to myself over email, I removed the old card and inserted the new one. You know, the one with the files that went through my PC before going to the media card. Guess what: all those old pictures are working. And my voice notes. I could view/listen to them all and send them to myself over email.

Fine. But why in the heck did the BlackBerry no longer recognize those files when they were on the old card? What if I forget to send everything to myself over email the next time I want to use the media card on my PC to copy music faster? What the hell is wrong with the media card encryption feature?