That sounds highly unusual; first time I've heard of this. We did have a bug, "Editing long notecards and scripts is interrupted by freezes" which was fixed.
Earlier in the year I thought, "One of the things I want to do on summer vacation is write a ton of new code in LSL." I have a big stack of ideas I want to work on. It's impractical because typing the name of a single variable can easily take ten seconds, so it's pointless to try to work with 100s of lines of code in a script that's large enough to trigger this problem. (For reference, the script I just tested is ~1800 lines.) I've already lost something like a month of development time (it started with 11.0) to this bug. I, and I'm sure many other scripters (and people working with big notecards, scripters or not) would greatly appreciate it if this bug was finally squashed.
Please note that testing the scripting editor on a 20-line lamp script, or something equally trivial, will not expose this bug. It will become glaringly obvious as you approach 2,000 lines.
