Read an interesting article recently noting that early voting ballots are more likely to be disallowed than in-person voting the day of the election. There's nothing nefarious about that: when you vote in person there are people there to answer your questions and help you if you have a problem.
This year the Democrat voters appear to be (according to polling) a much higher proportion of early voters than in the past (when the parties were roughly evenly split) and so it may turn out that many more Democrat votes than Republican votes will be thrown out this year.
Just imagine the controversy if the outcome hinges on a few votes in swing states.
Voting has been extended in recent years so that people can vote over a period of weeks. People don't have to speak English to vote in America. Even before the pandemic you could vote absentee (by mail) at your convenience.
The reason for the low numbers of votes liberals have garnered is apathy about their candidates (why should we vote for a crooked old white male anti-busing ass-grabber named Joe just to toss out one named Donald?). Possibly (as you say) Trump will inspire more of them to vote. We'll just have to see.
But the fact remains that even if (unbiased) robots were checking over all the ballots the mailed in votes would be more likely to be disqualified. Since Democrats seem to be bringing their troops to the battlefield this way more than the Republicans are, there will be more Democrat votes disqualified.
Perhaps. But the "normal problems" affect a much broader spectrum of ballots than the "rows". For example, in California there most likely won't be as much challenging (on either side) because California isn't likely to be a state in contention (or, if it is, it means the election is a landslide for Trump!). That still means thousands, even hundreds of thousands of ballots in California may be called into question by "normal problems" that will hit so much harder this year because of the early/mail balloting.
I wasn't speaking to which things get more attention. Think of it as snow in winter. Some of it is natural, you can't "blame" anyone for it. Some of it is the result of snow-making, you can "blame" ski resorts for "cheating". But the amount of natural snow, even nowadays with global warming well on its way, far outweighs the "cheating". And so it is with ballots. That's not to say cheating might not swing a tight election, especially in some swing states, but there is bound to be lots of press about ballots disqualified for innocent reasons and, since the Democrat vote appears to be more heavily weighted to early/mail-in voting which has incurred more (innocent) problems even in less-stressful years, the stories will have a partisan result.
If you read my post you'll see I was commenting on a possible reason for liberal apathy. I don't think it's likely that liberals (of whatever flavor) have been hiding under rocks (though maybe they've been fleeing to Canada?) for the last four years.
The "natural" disqualifications are, by their very nature, not "egregious" (at least in the sense that there is nothing deliberate about such disqualification - clearly it isn't a good thing to have spoiled ballots for whatever reason). I was saying that the QUANTITY of disqualifications for reasons that are innocent will be far greater than the QUANTITY of disqualifications perpetrated by nefarious evildoers, simply because innocent mistakes are committed by some fraction of all voters everywhere.