Totally normal even for infants. Why? Hormone fluctuations. With infants it usually only lasts a day, and might happen a few times a year. With toddlers (young... 1-3) it tends to last a few weeks. With older toddlers and young children it can last a few weeks to a few months, but usually only crops up every couple years.
REALLY common right around age 5. The first big 'bathing doesn't take care of it / needs deodorant daily' for a few weeks or a couple months. Which is right where you're at.
You'll note these periods tend to herald a new 'developmental phase'. Like you probably had a couple days of whiff right before terrible 2s (or 3s).
The 5ish hormonal swing (which changes face structure, hair texture, etc.) lasts anywhere from 2 weeks to 6mo on average.
(Also... I'm sure this isn't you... But just to avoid being snapped at... By 5ish, that's anywhere from 4 - 6. Months are super important with infants, but medically speaking milestone ranges after 3 get loooooong. So when I'm saying the 5yo hormone flux, almost 5yos are totally lumped in. Like I said, I'm sure you're not ghe type to freak about a couple months, but even this single paragraph saves 10 paragraphs later x_X Oy!! So I'm just sneaking it in preemptive ly!))
It's actually far more weird NOT to get BO with these hormone fluctuations, but most kids do. It just usually only only kids or the youngest who get noticed by parents as "Yikes! What happened to you?!?" Purely because there's fewer gross smells / time / etc.