For best results (!) try using the Chrome Browser. I've found that it crashes in all sorts of apps - but Chrome seems to be the most common.

i use copy paste a lot and have been using samsung phones since the day of release of the SGS1 and never encountered an issue like this

Can't reproduce either, International S3 with the current Samsung build of 4.1.2. Tried it with Samsung keyboard and K9 mail, but even after having a mail with 20+ times "File:///" copied over and over, nothing happened.

Also, I've had considerably less crashes on the S3 than on my previous N1.