Luni-Solar Sabbath Problem

Hello dear reader, in the past I have been promoting the Luni-Solar Calendar, however the luni-solar sabbath doctrine states that every new month the sabbath would be on the 8th 15th , 22th and 29th day, which seems to be impossible if we look at joshua 5:10–12 from which we can conclude that the manna ceased 2 days after the israelites kept the passover which was kept on the 14th day, that means manna would have appeared on the 15th cause it only ceased on the 16th and from Exodus 16:26 we can conclude that manna did not appear on the sabbath day, so if manna would have appeared on the 15th it could not have been the sabbath day,