depends what you mean by 'reproduce.'

if I save the buffer once, check it, see the problem, erase the file, and save it again, it does the same thing every time.

trying to create a buffer on purpose that won't be saved properly, is a different story. for one thing, the 'line wrap' of the text when saved, is different than in the query window. the query window lines might be split in the middle of a word, but the saved version doesn't do that.

without any indication of what is really causing the problem, any 'test' i produced could be completely useless. I could produce a buffer that I think is not being saved correctly because it has a certain number of lines, but the REAL problem is that the 5th letter of the 8th word on the 12th line is E.

sure, I know that shouldn't cause a problem. but the problem that IS happening shouldn't be happening either. in 30+ years of programming, I've seen some pretty strange things. anyone else remember pattern sensitivity in early microprocessors? I'm sure glad I didn't have to find that problem!

one clue might be that people who use contemporaneous logging don't seem to be having any problems. (or at least they haven't noticed/reported them.) so a good place to start might be to explore the differences in how those two functions operate.

perhaps the save-whole-buffer-at-once operation doesn't have long enough strings allocated to do something. it always seems to drop a whole line, and so far it always seems to be the FIRST line, including the <nick>

I thought for a while that it might only affect adding a query buffer to an existing file, but that doesn't seem to be the case.

and I haven't tried it recently, but I found in the past (at least with 6.14) that if you saved a CHANNEL buffer to a file, and changed the file name to something other than the channel name, it showed the right name in the status window but the file name that it wound up actually using for the save was a garbled portion of the original channel name, not at all what you typed in manually to use. maybe not related, but who knows?