Is the third lack of withdrawal bleeding with Slinda tablets a cause for concern?

According to the documentation of the drug Slinda, its characteristic feature is the occurrence of irregular bleeding from the genital tract when taking it. Bleeding may also not occur at all. Withdrawal bleeding (i.e. starting within 4 days with Slinda placebo tablets and lasting up to 8 consecutive days) was most common at the start of treatment, although it occurred in less than 40% of women and decreased over the course of the study - after 9 months of taking the tablets, withdrawal bleeding was reported in less than 20% of women. I enclose additional information about the drug Slinda - prescription preparations can be reserved at GdziePoLek and collected stationary upon presentation of the prescription: https://www.gdziepolek.pl/produkty/101505/slinda-tabletki-powlekane/apteki/w-warszawie