Originally reported by @BronzeShadow on the Hexerei Discord, you can see their post here: https://discord.com/channels/908547504587538463/911421279108747296/939496247310577674

To replicate: using the latest version of Hexerei (hexerei-0.1.14.jar) place an item frame anywhere and place the dowsing rod into it (game crashes immediately)

The original crash report from BronzeShadow: BronzeShadow_original_crash_report.txt

Crash report from my WIP modpack: alec_modpack_crash_report.txt

Crash report for only Hexerei mod using latest Forge in a new world + fresh profile:
crash-2022-02-05_11.45.03-client.txt

Crash log for just throwing it with Q (edited title also)
crash-2022-02-08_12.40.12-client.txt

Luckily loading back into the world works fine (the first time at least???)

Thanks to @frog from the Discord server for reporting the drop/throw issue and this bit also! 💚

fixed in the latest update (soon to come)