yup that could be part of the cause - as with anything else in this hobby, its rarely any one thing that caused it - how nutrient runs thru our system and how it impacts the growth of various organism is such a complex interconnected web of cause and effects that its very difficult to have a clear picture of every aspect of it.
Thats why "slow and steady" is emphasized so much.
Even in my 4 year mature tank, i get dinos sometimes (like right now). it happens every time there's a change in my check and balance. This latest "outbreak" is caused by me removing my fuge b/c i needed to start another round of vibrant to combat valonia fastigiata, which caused an increase in nutrient + removal of the macro algae competition - I'm not doing anything specific to treat the dinos as there's still a lot of biodiversity left in my tank - dinos just raced ahead by the vacuum left by the fuge removal + Vibrant killing algaes releasing nutrients. All i'm doing is blowing it off and scooping it up to keep it from getting out of hand and wait for the rest of my biodiversity to catch up and fill the void. usually it goes away after a month or so by itself (like the last time i had to go thru vibrant treatment)
In my younger days i may have freaked out at the sight of dinos and tried all kinds of treatments on day one which more than likely would have thrown my tank into further chaos and made dinos worse.