Change in daughter’s behaviour

So, as many of you already know, both myself and my youngest daughter (2 years 11 months) are autistic. Until recently, with anyone apart from me, she’d be “don’t touch me!” communicated physically by pushing people away or making noises at them as she is still mostly pre-verbal. She can also be tactile defensive with me on occasion but not often. She had started to get a bit better with my eldest daughter (22) a few weeks ago but then a couple of weeks ago there was a sudden big shift in behaviour. She been running up to random women at church; in the school playground when I’m dropping my 5 year old daughter off; at my 5 year olds swimming class; anywhere! Luckily she is quite ‘good’ and appears to have taken on board that she can’t climb on other women’s laps BUT last Saturday afternoon when we were in the spectator area watching my 5 year old’s swimming lesson, she went and sat in front of another woman and then when the woman’s son got in his mums lap, my daughter got terribly upset (she does this if another child including her siblings are cuddling me) and bless the woman she turfed her son off her lap to appease my daughter and then when the woman had to go because the swimming lesson had ended my daughter was in floods of tears.

Luckily all the women she has done this with have been very understanding and accommodating. She’s still young enough for it to be seen as cute BUT I’m aware of the vulnerability risk too! There’s a few things that occur to me as to why my daughter is suddenly doing this including’Inappropriate behaviour’ in as much as she has reduced awareness as to what is socially acceptable as compared to her peers; getting overly attached to people that she’s only just met very quickly. I don’t know. 
I just wondered if anyone else has any thoughts or insights to share regarding this?