Border control issue when visiting my partner

[Hopenotlost]

I've posted on here before, and am now back with some new questions and concerns which I'm hoping you could help me out with. I will separate them to avoid confusion, so this one will be about border control.

Briefly again, my British (unmarried) partner (living in the UK) and I (Russian citizen living in Russia) have been in a long-distance relationship for about 5.5 years. We have a 4 year old daughter together who was born in Russia but is a British passport holder. We each have ties in our respective countries which is part of the reason we have yet to find a way to live together as a proper family, though it is mostly being made difficult by the fact that I am a Russian passport holder with few options as far as relocating. At some point last year my eldest daughter (one of my 'ties') was going to move to another country where her father, my former husband, resides, at which point my partner and I started looking at the possibility of our young daughter and me relocating to the UK. But, the options weren't looking good to us, and then my eldest daughter decided to stay with me after all so we put that plan on hold once again. To allow us more time to find a workable plan I opted for another long-term visit visa (a 5 year multi-entry after a 2 year one) which I got without any issues whatsoever and have since used to visit my partner. Now until I got that last visa I never had an issue - border control had always been always plenty nice to us, asking all of the same questions, getting all of the same answers, even sympathizing with our situation, it seemed. Then I arrive at my beloved Heathrow on my brand new shiny 5 year visa, get asked the same questions except instead of a sympathetic nod I, along with my then 43 month old, get sent to a waiting room - no explanation, no documents but some paper on detention and suspended leave to enter until further notice. Scared me to death, I'll admit, but half an hour into what felt like the longest wait of my life we were handed our documents and told that we were free to go. Shaken up as I was - and my partner thought it very odd, too - we figured it was probably some random check thing so let it go. Our daughter and I came back for New Year's, and, you've gussed it, same story, except a bit worse. 40 minutes or so in the familiar waiting room after which we were told to get our cases so that a big man could look through my underwear and my little one's New Year pressies (they went through both our checked in lugguage and carry-on bags, counted the money in my wallet - everything!) to then tell us we had to go back to the waiting room while they ran more checks (?) Oh, and they also asked if I'd ever been convincted of anything in the UK! (???) About half an hour later we were let go, but I failed to get any reasonable explanation from the border control officer lady who, well, did that to us (or had been told to?) She said something about how "it should now be easier" with my five year visa (but this has only happened since I've been on my five year visa!!) and then that my visa was new (it was my second time traveling on that visa!!), and also that apparently she did everything she could to get us out faster - um, ok, thanks?

Any idea what could be happening here? Ok, granted, our situation would raise eyebrows, but I had just put all of our info, our living arrangements included, on yet another visa and got it! Have I been put on some kind of black list? Why? Could it have something to do with our calls to UKVI last year about a settlement visa? Then again, surely, had they had any concerns, they would not have given me a five year visa?

While my partner is about to write a complaint (any idea who he'd be best off contacting on the matter, btw?) I'm still kind of freaked out, and I must say that until I believe that this has been sorted I am not exactly looking forward to another trip to the UK if it means putting my little girl through another warm welcome. She didn't deserve the two that she got, and, to be honest, neither did I.

[CR001]

The IO at the airport have every right to question you, search your luggage to make sure that they are satisfied that you are a genuine visitor etc.

Many people go through this, it is not discrimination or anything of that sort. They are only doing their jobs.

[Hopenotlost]

Thank you for your reply.

I'm still not sure I understand why they must do this to somebody who had been in and out of the country, well, many times, is on their second long-term multi-entry visa and, most importantly, had already been checked (for whatever reason) just five months prior...

Also, I had never been through anything so humiliating in all of my years of traveling (to many different places) so I do take it personally