I don't know if it's a bug, but when you summon an entity with a tag, it doesn't spawn with items in hand.
Example command:
/summon skeleton ~ ~ ~ {Tags:["Test"]}
So far I know it's in every minecraft version, so that's the reason why I don't know if it's a bug or not.
Thank you for your report!
However, we are already tracking this issue, and this report is a Duplicate of MC-86172, which has been marked as Works as Intended - this is an intentional game feature. If you have a different opinion, please visit the Feedback website.
Please use the search function in the future to prevent duplicate reports.
Quick Links:
📓 Issue Guidelines – 🛠 Community Support – 📧 Customer Support – ✍️ Feedback and Suggestions – 📖 Game Wiki
💬 Mojira Subreddit – 💬 Mojira Discord