Coding follow-ups before interview loop?

Just curious if this is common or what; haven’t interviewed outside of FAANG in a while. Scenario: - screen call with HM (30 min chat, 30 min code) - recruiter reached out saying HM feedback was positive, scheduled interview loop. - HM emails: “can you please extend solution to added requirement X” - Done. - HM: “can you also implement this” - Done. Chose 1 of probably 3 viable implementations. - HM: “can you explain why you chose that way and compare with alternatives” I always provide ample test coverage to demonstrate each corner case and expected output. I keep doing the asks because the team interests me, and I think maybe they’re trying to make a leveling decision, but it seems strange to be doing all this before I even do my upcoming interview loop. Low-key I feel like I might be solving a task for them because the project isn’t dissimilar to what the team does. 😂 Hopefully, they’re just comparing my choices vs their own leads’ designs and not using me for free labor. I’ve been given take-home projects earlier in my career, but this is new to me. Anyone else seen something like this? TC: 290k YOE: 5