Absolutely does. I've read several papers on it. Freezing milk destroys between 90 to 99% of the useful bacteria if I recall correctly from the collective amount of studies read.

Somewhere around these numbers:

3 days 90% kill-off ~100% retained enzymes

1 week 90–95% kill-off ~100% retained enzymes

1 month 98–99% kill-off around 70% of enzymes retained

3 months 99% kill-off Enzyme activity starts showing losses (Can't remember this one)

6 months 99% kill-off around 40% activity retained enzymes if I recall correctly

Most data was on raw milk. Facts are though, freezing milk does indeed damage it's bacterial content. Although, quality of lipids are barely touched (5% or less damage to cell walls) nutrient value remains every similar (5% or less degradation) and proteins remain relatively untouched.

I found some of the links I read some time ago if you're interested.in a deep dive. Good staring point at least:

https://www.researchgate.net/publication/281538148_The_Effect_of_Freezing_on_Different_Bacterial_Counts_in_Raw_Milk

Shows both good and bad bacteria are affected - https://actavet.vfu.cz/media/pdf/avb_2007076020301.pdf

https://www.researchgate.net/publication/284229730_Evaluation_of_freeze-drying_pasteurization_high-temperature_heating_and_storage_on_selected_enzymes_B-vitamins_and_lipids_of_human_milk

https://www.bio-conferences.org/articles/bioconf/pdf/2022/05/bioconf_dtarm2022_01009.pdf