There is a plugin called ReMate which should fix the problem.  If you are editing files over a network share, this is bad news with TextMate and will probably eventually crash and lose your work.  Be careful.

http://ciaranwal.sh/remate/
 
When i open a folder on textmate, in this case, kohana stack. I open e
file writing some code. Then save it, goto chromium to check. Now when
return to textmate, textmate freezes and takes 100% CPU, after some
time, 5 to 20second, everything comes to normal. This happenes every
time textmate lost focus then got focus again.
step to reproduce,
1. Open textmate and open a file.
2. Goto another app while keeping textmate open, In a word,make
textmate lose focus.
3. Return to textmate, In a word, make textmate got focus.
=> Cpu usage goto 100% and textmate hangs.
I'm suspecting that when getting focus, textmate scans the files for
changes outside textmate, is that it ? if so, is there any workaround
?