As of version 1.16.100, it is no longer possible to strip wood blocks using an axe. The prompt still appears, and logs, stems, and hyphae can still be stripped but "wood" blocks cannot.
Tested both on a survival realm and on a creative single player world. This was not a problem before (as of time of writing) yesterday's update.
Thank you for your report!
We're actually already tracking this issue at MCPE-105998, so I will resolve and link this ticket as a duplicate.
If you would like to add a vote and any extra information to the main ticket it would be appreciated.
If you haven't already, you might like to make use of the search feature to see if the issue has already been mentioned.
Quick Links:
📓 Bug Tracker Guidelines – 💬 Community Support – 📧 Mojang Support
📓 Project Summary – ✍️ Feedback and Suggestions – 📖 Game Wiki