It could be, but they seem to get through Cloudflare’s JS. I don’t know if that’s because Cloudflare is failing to flag them for JS verification or if they specifically implement support for Cloudflare’s JS verification since it’s so prevalent. I think it’s probably due to an effective CPU time budget. For example, Google Bot (for search indexing) runs JS for a few seconds and then snapshots the page and indexes it in that snapshot state, so if your JS doesn’t load and run fast enough, you can get broken pages / missing data indexed. At least that’s how it used to work. Anyway, it could be that rather than a time cap, the crawlers have a CPU time cap and Anubis exceeds it whereas Cloudflare’s JS doesn’t – if they did use a cap, they probably set it high enough to bypass Cloudflare given Cloudflare’s popularity.