%Event-video_name% Looks like the literal string from your Launch Data Element....
This can happen if your implementation changed the name of a Data Element, or someone made a typo and no such Data Element exists.
To be honest, the mix of "-" and "_" makes me suspicious that the Data Element is just being referenced incorrectly. Check your Launch implementation, look at your Data Elements, make sure the Set Variables rule(s) are using the correct Data Element name. (If the name was updated after the rule, I don't think the rule will auto update... the Data Element's new name must be set to your dimension.)
%25Event-video_name%25 looks like an encoded version of the above... %25 is the html encoded version of %
Given the much smaller number, I am going to assume one odd browser (possibly a bot or an older version of a browser) is just encoding the literal value; but this is the same issue.. your Data Element doesn't exist...
