Currently in game, rolling a natural 1 on any check automatically fails you without taking into consideration any bonuses or even the original DC - Larian have confirmed that this is their change and is working as they intend. All we can do is bombard them with regular feedback to tell them that natural 1s are not auto-fails on skill and ability checks, or saving throws, and should only apply to attack rolls (and the very specific death saving throw), and to ask them to change their mind about this.

You can do so on their bug report form, here: https://larian.com/support/baldur-s-gate-3#modal

In terms of the RNG, Larian have been shown to use an RNG that doesn't source its chaos variables well enough, or regularly enough, and so its roll pattern creates a visible sine wave of variance, where other contemporary games do not.

https://docs.google.com/spreadsheets/d/1tdyBoQNS_vwEGZGBgFRQex7b-Ma8S6P7zvEMK5wh9n4/edit?usp=sharing

This record was made in an earlier patch - You can see that while the RNG ensures that the balance of numbers comes up within the average bounds, the actual distribution creates a visible algorithm pattern that you can legitimately track in game.

I've not had the stamina to re-do the numbers since then, but it was before they introduced loaded dice as a 'fix' to the RNG complaints, so I've got little confidence that they've actually improved their base RNG. If you're not using loaded dice, you'll experience this - if you are, you'll experience an even more visible correction effect that will do you dirty as often as it helps you.