Adventuring Time achievement is not triggering after exploring 17 biomes. There are indications in forums and discussions that this can trigger randomly after an unknown precondition is achieved (possibly related to maps). 

Attached are screenshots of a PS4 account with all basic achievements except Adventuring Time (and the following all achievements achievement) and a map wall of 4/4 maps indicating the explored world created by this account in bedrock (it was not a migrated world from LCCE but a new world in 1.14).  This world is survival and was used for all other achievements.