If these smart lists normally work for you and you haven't changed anything I'd definitely recommend reaching out to the support team! Sometimes filters for activities that happen frequently can slow down a smart list load time or referencing too many other smart lists, but if you use these regularly I'd definitely ask support. I was having issues yesterday with just general slowness in Marketo so there may be a larger issue as well. Hope everything is sorted out!
Thanks so much! If it doesn't clear up soon I think I will escalate it to our support contact!