People hate emissions equipment the knee-jerk reaction is to blame it first and foremost for any problems in the automotive industry. To me, the data indicates that COVID impacted heavy truck pricing the same as it impacted cars, other durable goods and heavy equipment.
Also, this article is n=1 of a low mileage example of a vehicle that doesn't often see so little use. If you hunt around auctions, you'll find tons of examples of pristine vehicles going for absurd prices. This does not represent a trend, for that, we'd need to look at wholesale prices of used equipment and compare it to general and industry-specific inflation figures in order to show that prices are increasing due to factors beyond inflation and availability.
There's even a tacit admission to this fact in the article, pointing out how the auction of a low-hours post-DEF truck also fetched very high prices.
The most obvious explanation is that the people seeking out assets as an inflation hedge are broadening the scope of assets they are interested in. Auction quality vehicles have been a solid bet post-2020, even after fees. This truck will probably surface again in a few years at a 30% higher price.