Transaction log shrinks on its own every evening

[Indianrock]

Our Lansweeper database is now sitting on an instance of Sql Server 2012 Enterprise. As of a few days ago the database transaction log mysteriously shrinks itself to about zero size every evening around 6pm. I don't mean the file itself remains fixed but the contents are truncated --- the file size itself drops from 5GB where I set it to zero.

Since I have sql server agent jobs set up to rebuild indexes nightly, I want the log to remain at about 5GB. So far I haven't found any windows scheduled tasks that would do this on either the lansweeper server itself or the sql server.
I'd really like to get this turned off but can't figure where to look.
Randy

[Hemoco]

We personally don't perform any additional database maintenance. We checked with development and they do indicate that the shrinking behavior may be changed in a future update. It isn't really necessary anymore. Lansweeper used to perform the entire database cleanup in one go, resulting in a huge log file, but now does this in small batches.

[Indianrock]

Thanks. For now I'll change my index rebuild to do its sorts in tempdb. Or perhaps I don't need to run index maintenance at all if Lansweeper is handling such things itself ??

[Hemoco]

The Lansweeper service automatically shrinks the log when a database cleanup has been completed. Database cleanups are performed when the Lansweeper service is started and subsequently every 24 hours. You cannot change this behavior.

[Indianrock]

Seems like nobody else has experienced this. I looked in the Lansweeper web console/configuration and sure didn't see process designed to do this.