Tried transferring two (one amplified with large biomes, one default. Both with large world size) of my completely survival worlds with absolutely no cheats from PS4 Edition and both resulted in cheats being turned on and trophies unable to be earned.

EDIT 2 I was able to transfer over my worlds successfully without getting cheats turned on in Bedrock by setting my world settings to "default" in PS4 Edition first, and by "default" I mean the world settings the game would have turned on or off if you create a new world without tinkering with anything. Such as: PvP on, fire spread on and tnt explosiones on, also turned back on autosave.

I'm not sure which one causes cheats to be turned on once it's transferred over to Bedrock but it's one or multiple world settings that causes this it seems, such as:

• PvP
• Fire Spread
• TNT explosions
• Autosave

As for how to try to reproduce this bug, I would say to start off by making a survival world with no cheats in PS4 Edition and turning off these 4 world settings, PvP, Fire Spread, TNT explosiones and Autosave, and then converting over the world. 

Try different combinations or one by one to see which one is causing cheats to be turned on in survival worlds once converted to Bedrock from worlds with no cheats in PS4 Edition