Research time shortened by laboratory upgrade

Ok here is what I did.

th7 th8 upgrades

had goblins upgrading with 4hrs left roughly when I upgraded the laboratory.

after laboratory upgrade goblins continued.

went into laboratory clicked on dragons - said upgrade already in progress.

went in clan chat watched a replay and when I came out said goblins have finished upgrading.

Tried to recreate with dragons with no success. Think you need to upgrade laboratory for bug to take effect

i know 200% I had 4hrs left on goblins.