Tasha never lied to Andrew. Even after the date with Charlie, Tasha spoke to Andrew about wanting to get to know other guys and his response was that that was fine because he was still open to getting to know other girls. I don't think he was, but she believed what he was saying. I think the issue is that Andrew didn't relay that conversation accurately to the other guys. He made it sound like he was 100% for Tasha and she wasn't as in to him. So Dami and Luca have been blaming Tasha ever since for something that didn't even happen.
And Tasha "being a bitch" to Andrew after not being picked by Charlie wasn't even as bad as people are making out. She was upset because Luca and Dami were rolling their eyes at her and being rude. Then she told Andrew to get off her in bed because she was upset- is it not quite normal to not want to be touched when you're in a shit mood? I'm the same
And the whole "I don't feel like myself thing". I've said this before, but all the OG women seem less confident as the series has progressed. Maybe Tasha assumed that that was due to her couple, when actually I think something about the "vibe" in the villa is affecting them all. When they were in Casa one of the others (can't remember who but I think Ekin or Gemma?) actually said to Tasha, "we've seen a different side to you here". So she clearly was different in Casa, and probably made the (understandable) assumption that it was because of Billy Vs Andrew, rather than realising that actually she was just thriving being away from the blatant misogyny of the OG men.
Even Tasha whispering to Billy in bed was just her insecurities speaking. She was scared of committing to one guy in case it meant she was missing out on something better. I don't think that's bitchiness, I think it's the immaturity of someone who's never had a long term relationship before and is intimidated by the thought of that commitment. I think a lot of people have those fears, Tasha's just unusual in that she actually admitted it out loud
I promise I'm not Tasha's dad
I just think a lot of how she's been portrayed is due to Andrew not being honest about his feelings and Luca and Dami finding an excuse to be dicks to someone.
ETA- Omg I'm sorry I didn't realise this was so long
I'm just filling the time until I have to rinse my hair dye out.