Seen here, I figured it should be reported even though I haven't reproduced the issue myself: https://www.reddit.com/r/feedthebeast/comments/8q2rt5/sevtech_ages_why_does_my_character_sometimes_pick/e0g11q0/?context=10000

This may be a vanilla issue: https://bugs.mojang.com/browse/MC-10657
There is a fix submitted to Forge: MinecraftForge/MinecraftForge#4974

Nice, thanks for the link to the PR.

That PR has been merged, so this should hopefully be closable now.