Special elections are always difficult for the prevailing party. The challengers make a greater impact by percentage when they use old-fashioned GOTV (get out the vote) techniques.
There were some state races in Oklahoma last year where seats flipped parties because of the timing.
It is, as you suspect, so very important that every voter exercises their right to vote. I don't think, at least in this race, that tomfoolery was at play.
It's a crazy tough time of the year to hold a final election.