Hard to say what would be expected probably a minimum of 50% down. Might be some special workaround considering they have orders fulfilling every last month, this month and then again in February for 1000 miners each go.
Apart form some decent direct contact with an account manager I don't imagine they step up their warranty game that much. They likely put the onus on the customer to have trained techs, through Bitmains certification process and then charge them for parts, as opposed to forcing returns for repair. In the end it's easier for them to sell off bulk quantities than deal with individual sales, it just leaves individuals to fit for the remainder.
Typo fixed. Actually looking at the linked report their revenues are up compared with 2019, they state 11%. They do mention Q2 being down 500K from 2019, but that is explained by their downtime in moving their mining operations, the halving and they say diff increases. The latter isn't as relevant as that should be expected, but the first 2 make a lot of sense to explain that small snapshot.
This is likely to turn around now with the recent price increase, the fact that they've been steadily adding gear for the last 4 months and plans to grow outpacing diff increases.