Zinnias (tall, not short) are flowering; NOT coming in true to colour! --> explanation below

I like the timing of when I sowed this year's zinnia seeds, because a good number of them are now opening into flowers, so I can decide what colour will go where.  (Well, for the tall ones, anyway.  The short ones are behind, have not started opening flowers yet.)

However, they are NOT coming in true to colour!

How interesting.

I'm going to post the following question and see if I can gain some insight.

Zinnia seed-saving question:   Is it normal for zinnia seeds collected from one colour of zinnia, to produce flowers of a different colour?  I'm getting a variety of unexpected colours. For example, some of the seeds I collected from last year's orange zinnias are producing pink flowers; some of last year's orange zinnias are producing red flowers; etc.  There seems to be a strong leaning towards pink.  All of these seeds were collected last year, from plants I started from seed by collecting the previous year (2018).  The original 2018 seeds were hybrids from a packet, so I wasn't surprised in 2019 when the colours weren't as expected.  But I thought moving forward, starting this year, the colours would be true to the colour of the flower from which the seed came.  (I carefully labelled last year's collected seeds and this year's seedlings, so it shouldn't be a case of mis-labelling)  Does it take several generations to get zinnia seeds that are true to the parent colour?  Or since the original seeds were hybrids there are no guarantees, even several generations later?  I appreciate any insight!

Edit!  Before I had a chance to post that question, I came across the following info, which explains it all.  Mystery solved!  Therefore, in future years, I will keep carefully keeping track of the colours (for interest's sake), but will also buy yellow seeds to be SURE to have YELLOW flowers each year.

"...even if the original zinnias were not hybrids, a certain amount of natural cross-pollination surely occurred in your garden as the birds and butterflies carried pollen from flower to flower. This means that almost all flower seeds you collect from a home garden will result in a mixture of colors the following year. In other words, if you save seeds from pink impatiens or petunias, the flowers won’t necessarily be pink the next year. You’re likely to get a random mixture of colors instead. Same goes for most other flowering annuals, though some cross-pollinate at higher rates than others." -- https://archive.triblive.com/lifestyles/home-garden/its-a-fun-gamble-to-collect-and-save-seeds-from-flowering-annual-hybrids/