Hi Andrij,
that's because the ID field in the UploadCampaign for Ukraine -
<https://commons.wikimedia.org/wiki/Special:UploadCampaign/wlm-ua> -
is left empty. And that's probably because nobody of the people that
took care of turning on the campaigns noticed that, or maybe because
nobody (or only a few amongst us) can write Cyrillic -- apologies for
that.
You are an UploadCampaign editor yourself, so please fix it (these are
fields 6 and 7 looking from the top of that page).
Thanks,
Tomasz