Tariel,
you shouldn't operate on LL defined in "repeat" condition:
The correct loop:
repeat for each line LL in TestLog
put LL into bLL
if last char of bLL <> comma then
put comma after bLL
-- HERE LL with line 2 of TestLog gets replaced
-- by previous LL which was holding line 1 of TestLog
end if
add item 2 of bLL to tTest
end repeat
VTB