The world is not using experimental mode. I exited the game and the save took longer than normal. The size jumped up from 23.5 MB to 260! I looked in the world folder and found an ~240 MB log file. I deleted the log, but exiting the world again recreated the log, 6 MB larger this time.
MCPE-31921
Worlds Jump Up To 250+ MB
Resolved
Duplicate
1
Mark Roger
(Unassigned)
Unconfirmed
Windows
Windows 10
1.2.14.3
Retrieved
Thank you for your report!
However, this issue has been closed as a Duplicate of MCPE-23462.
Your additional information and observations are very useful, so if you can add them to the comments section of the parent issue it would be appreciated.
If you have not, you might like to make use of the search feature before making a new ticket, as it's likely that the issue has been reported already.
Quick Links:
📓 Issue Guidelines – 💬 Community Support – 📧 Feedback – 📖 Game Wiki