XP not granted when killing mobs with fire aspect sword

We do not have enough information to find the cause of this issue.

Please record a video of this happening and attach it to this report.
If you are on Windows, you can use Windows+Alt+R to open a built-in app for recording game footage.
If you are on Mac (Mojave or later), you can use Shift+Command+5 to open a built-in app for recording your screen.
In case you don't have a program to record videos, we recommend using the free recording software OBS.
In case the resulting video file is too large to be uploaded to the bug tracker directly, please upload it elsewhere (e.g. as unlisted video on YouTube) and link to it here.

_{This issue is being temporarily resolved as Awaiting Response. Once the requested information has been delivered, the report will be reopened automatically.}

Quick Links:
📓 Bug Tracker Guidelines – 💬 Community Support – 📧 Mojang Support (Technical Issues) – 📧 Microsoft Support (Account Issues)
📓 Project Summary – ✍️ Feedback and Suggestions – 📖 Game Wiki

Can Not Reproduce. Tested against a fire-immune mob (Zombified Pigmen) and they still drop xp. The user likely made the bug report since fire ticks from ignited mobs that are killed by the Fire do not drop xp since fire is not inherently a player kill.