Hey Timon,
you’re absolutely right, I was able to replicate the bug, this is indeed my fault – thank you for bringing this one up! I’ve prepared as fix, which will be included into the upcoming 3.1 version update for Ikebana (due to become available this week); meanwhile, you can download this archive, unzip it, and upload the resulting file into the primary theme folder (/wp-content/themes/Ikebana/), replacing the existing file. Please let me know if it corrects the bug!
Sincerely,
Andrii / Satori Studio