You saw coincidences and your monkey brain groped for an explanation.I did see a pattern when I was able to pay in to it . Over the years I worked out I was getting better prizes and more frequently if I was to buy them at the end of the month before the draw on 1st or 2nd or 3rd.
Also . Noticed differences in £1k Vs 3k
The Government Actuary’s Department (don’t ask me about that apostrophe, I didn’t name it) say it’s random. I believe them. If there were a pattern, someone would have proven it at some point in the last 68 years.