Using Loki and Carol.
Four Mischief countdowns.
When the first one expires Carol won’t boost the special tiles, she start boosting only after the second Mischief countdown expires.
I may be wrong, but I think this is a display bug. The animation starts after the second one but then happens twice after the last.
It’s not only with loki. If multiple countdown tiles expire on the same turn the first seems to go unnoticed. However, it does count on the buff. Seen this with sentry, coulson and im40