Stranger giving food to 5 month old

[Titch1993]

AIBU here, or am I overthinking....

Doing the weekly shop with DS1 (2years old) and DS2 (5months).

Due to really bad reflux thats not going, have been advised to wean DS2 a little earlier (tried to persist until 6months). Anyway, was explaining to DS1 about the veg that we were buying to hopefully help DS2.
Random lady comes up to us (don't know her at all) and says you need to fatten that boy up (referring to DS2 - HES 98th centile height but on 25th for weight so looks a little thin but has improved so much). Opens a pack of chocolate biscuits from her own trolley and gives one to DS1 and DS2. I took it quickly from them and explained DS2 was only 5months and we are trying to start solids etc. She did apologise and said she thought he was older. She then started telling me that sweet potatoes rot teeth and to try carrots... I just stood in disbelief, didn't know what to do or say!
I'm still a bit shocked, just don't really know what to think! Its been bugging me and I just wanted other people's views!

@user1471453601 didn't see her open them, I'd turned to get some sweet potatoes (hence then the comment about sweet potatoes). As I turned back she was handing them over. I'd have definitely stopped her sooner otherwise. Just didn't occur to me someone would do something like that.

@firstimemamma now that's a bit

@Wellpark

She sounds disinhibited. Perhaps she's is having a manic episode. Sorry if that is outdated terminology to describe bipolar bevaviour

For goodness sake! She was in the wrong for giving biscuits to children she didn't know, but to say she might have bipolar disorder is ludicrous. When did you qualify as a psychiatrist Wellpark? Or even (it's a long shot) if you are one, how could you possibly come to that conclusion?