In /etc/cron.daily/tetex.cron as enclosed in tetex-1.0.6-7, there is a
comment saying that fonts are removed if not used in 10 days. Then there
is a command removing fonts older than 2160 hours, or 90 days.
I suggest you change the comment.
*** Bug 10613 has been marked as a duplicate of this bug. ***
Fixed in tetex-1.0.7-9.
*** Bug 28032 has been marked as a duplicate of this bug. ***