That is my suspicion. LingQ is a fairly niche application with a fairly small user base, likely making a fairly low amount of revenue*, based on fairly old software. It’s probably stuck somewhere between being a profitable business and an enthusiasts’ hobby project, hence the difficulty addressing underlying bugs and annoyances and the seemingly unprofessional way they release updates without enough testing to spot critical bugs ahead of time.
To put it another way, I suspect LingQ the company is doing a bit of a balancing act, offering an ambitious niche product that’s hard to make profitable enough to address major issues.
(*We individually pay a decent amount, but I suspect to really pay for the necessary fundamental revisions, the price would need to be quite a bit higher - at which point many of us might cancel, so their revenue might not even grow enough from such a price hike.)