Shedding when switching brands of finasteride

I used Minox for 9 Months now, didn’t see much of difference in my diffuse hairloss as I always cut it short. However 4 months ago, I started taking Finasteride 1mg, microneedling 1.5mm every week or 2 weeks. I saw huge improvement in my hair in the last 4 months (Pictures of improvement after 4 months Microneedling+ finasteride are attached to the mail). I used a german brand Finasteride called “Finaristo”. Now since a month I switched to another generic Finasteride 1mg from “Relonchem” shipped from a registered NHS UK pharmacy, because it’s much cheaper than here in Germany. I am now shedding like crazy and this is the first time I notice a shedding in my whole treatment regimen. would you recommend me rebuying the expensive generic german brand so I don’t lose my results? or is it a normal shed at 4th month of finasteride that should go away? And if goes away, how long until it does?

Maybe the new medication is not what you are thinking you are buying and if it is a counterfeit, then that would explain the shed