There was a change in US tax law that revoked the ability of software companies to classify engineer salaries as an R&D expense, which massively increased the tax liability for many software companies.

This is under-recognized by many folks. That full impact of the that aspect of the 2017 TCJA was hard to predict when it was so far in the future, and when it hit, we were dealing with the latter economic impact of covid in addition to these deduction changes.

This was reverted for us employees in OBBB and companies can refile taxes for what they couldn't use as an expense in the intervening time. I think the impact of this is generally overstated