In the beginning everyone thought Sid was a super angry unreasonable man, and everyone kept complaining to him about it but it took Salman a while to acknowledge it. BB gave subtle hints (such as saying how can Sid be so logical yet aggressive), but until BB clearly expressed that Sid was going in the wrong direction (2 week automatic nomination), Sid finally realized this aggressive worked so far but has to now stop. Then, he switched his game and now - seeing Salman enjoying the Sid/Devo drama during the waxing task he is doubling down on it. Sid is really good at one thing - and that is taking feedback. Mahira, Paras, Rashmi get feedback as well (sometimes embarrassingly via Salman), but even then they don't tend to think from the audience's perspective. Sid has taken every hint he is given by the show/Salman and immediately takes effect. When Salman expressed that Sid/Sana were both favorites during their fight, Sid realized that he needs to patch up with her and in the first chance he got (when she came to him when he was sleeping) she hugged him. Similarly, when Salman expressed that Asim is the only guy who doesn't look diplomatic in the house, Sid hugged him as soon as he saw the window of opportunity (when Asim was casually offering him hairspray). This shows that NONE of the personalities Sid has shown so far is his real one. The only thing he really know about him is that he is very intelligent, he is totally self aware that he is on a show (ie he doesn't get lost in the house and is aware that cameras are around him), and he can take feedback well.
And this itself is what is bugging Asim. Sid's skill in playing the game is becoming clearer and clearer, and in Asim's eyes, playing the game = being 'fake' and the reason he connected with Sid in the first place is because he was real. When Sid, who himself insisted that Asim do not have fun and hangout with the other team members, is now flirting with Devo and joking around with Mahira - of course its frustrating! For this reason, I think Asim will be the fan favorite soon. After a few weeks, Sid's game will be clear to everyone (in and out of the house) and Asim will emerge as the real guy.
ONLY thing that will stop this natural process - Salman/channel insisting on Sid being portrayed as the hero. If focus on Sid is loosened up a little bit, I think the entire game can flip.