I've been hitting this bug for several days, and it's definitely related to MCPE-19688.

Description: Opening inventory in certain states causes the game to crash on win10. This is related to enchanted armor in a invincible state. The same game can be opened on iOS, but it still behaves strangely.

Detailed history: I had a full set of enchanted armor and went into the nether. I died, killed by several blazes at a blaze spawner, and trying to retrieve it, died again. I went back again and managed to retrieve it, but opening any chest or inventory led to an instant game crash. I found elsewhere on here that switching to the pocket UI (from classic) would be a temporary fix for the problem. It worked, and I was able to put my enchanted armor back on. However, I noticed that the damage bars were gone. Playing with this armor for a while and fighting, it never takes damage.

I tried a couple of experiments. I took everything else out of my inventory and made an empty chest. The first thing I did was to take off my armor, which resulted in an instant crash. Loading up my character in the realm also resulted in an instant crash. Desperate, I purchased the iOS version to try to rescue my game. In the two attached screenshots you can see that the armor shows in my personal inventory, but not when I exit personal inventory. It also will not show in a chest inventory, so I can't get rid of it or put it in a chest.

I believe that the reason that this causes a crash in classic UI is that on Pocket UI, the armor screen is a separate tab. On classic, when you open your inventory, your armor always shows. Something to do with this invincible armor rendering in hand or in that initial inventory screen is causing the crash.

I've tried throwing enchanted armor out in the nether and picking it back up, this doesn't do the trick. I've also tried throwing it in the nether, leaving and coming back, this did not work either. Something about dying and returning may have made the armor invincible but I have not been able to repro this yet.

Screenshots attached from iOS.