Start a new spreadsheet, or open an existing one, and toggle Edit -> Track Changes -> Record. => The spreadsheet doesn't become modified, if it's closed without explicitely saving it, the change in the setting is lost. Observed in LO 7.2.0.0.alpha0+ (2c9708cbb870483a8a1c93d722085be5f789d234), 3.3.0 / Ubuntu. In Writer this is working fine, already in 3.3.0.
Justin Luth committed a patch related to this issue. It has been pushed to "master": https://git.libreoffice.org/core/commit/55ee3ede2bb0211e895053ed3a54bb1c99cc94ca tdf#139480 sc: Un/Track changes now marks spreadsheet as unsaved It will be available in 7.5.0. The patch should be included in the daily builds available at https://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More information about daily builds can be found at: https://wiki.documentfoundation.org/Testing_Daily_Builds Affected users are encouraged to test the fix and report feedback.