The written warranty governs coverage and explicitly says that "No person has authority to enlarge, amend or modify this Limited Warranty". That said, Heartland Senior Management could decide to issue some type of official, written, warranty modification. Or on a case-by-case basis, Customer Service could grant goodwill accommodations based on the circumstances. They often do that.
I might be wrong, but I thought most RV dealer repair shops were open for business. If that's the case, Heartland might not see a need to do anything.
For anyone who has a specific problem, now, and there is no dealer open anywhere near you, you should call. They might grant an accommodation to get that specific problem taken care of later in the year.
If the concern is that you've lost a month or two of potential use where problems might have arisen, but haven't, I wouldn't hold my breath. Most people lose many months of their warranty just because camping season for most is not year round.