Please help! Faint lined turned into nothing after time frame passed. Is this normal?

Kathy • Baby Boy - IUI - November 2019 Baby Girl - IVF - January 2023

So, I know I shouldn’t look after the allowed time frame but did anyway. I had a noticeable faint line around 3 min mark. After about an hour I went to check it again with no sign of a line. Is this normal? Was it really a BFN after all?

Noticeable faint line. 10 DPO. First fertility appointment scheduled for tomorrow after 1.5 years TTC. (Top 2 pics)

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Line gone after an hour-ish (bottom 2 pics)