So my traditional catholic calendar had ember days as last week, but my parish bulletin has it as this week... I am confused.

In the Roman rite the September Ember Days were always kept on the Wednesday, Friday and Saturday after the feast of the Exaltation of the Holy Cross. In the Breviary this was the third week of September.

As G.B. notes above the 1960 rubrics, which came into force on 1st January, 1961, changed the way the first Sunday of the months of August, September, October and November was calculated. In the traditional system the first Sunday was that closest to the 1st of the month so, e.g. this year, Sunday 31st August isconsidered the first Sunday of September. In the new rubrics, R.G. Ch. III, 19, this was changed so the first Sunday always was counted in the actual month.  So, the first year this would have made a difference to the Ember Days was 1964. In the new system the Ember Days were kept on 23rd, 25th & 26th, a week after they would traditionally have been kept.  It may be the case the reformers didn't consider the effect the rubric would have on the Ember Days.

The Divinu Afflatu calendar and rules put the September Ember days on this past week, 17th, 19th and 20th of September, while the 1962 missal says that it is 24th, 26th and 27th of September.

It has to do with a different method of counting weeks that was put in practice with John XXIII.

You can access this website and see the differences between the missals and calendars: www.divinumofficium.com

So if you believe Roncalli et al. were legitimate popes, then, well, they eliminated ember days entirely.  But if you're SV, then they were last week.  So the only mandatory ones were the ones this past week.

So if you believe Roncalli et al. were legitimate popes, then, well, they eliminated ember days entirely.  But if you're SV, then they were last week.  So the only mandatory ones were the ones this past week.

I was going to ask about this.  I didn't think there were any Ember Days in the Conciliar sect, and you answered the question before I had the chance to even ask.

But sedes believe that Pius 12th is a valid Pope. Why wouldn't they accept ember days as this week? And isn't it a mortal sin to skip if you don't believe in the v2 church?

There were many Papal indults that dispensed people from a certain country or a certain diocese from this or that fasting or abstinence day. It is very difficuld to find this kind of information online. I don't know the practical rules for Sedevacantists these days, since these indults changed from place to place. You basically have to find out what was the situation on your area when Pius XII died, which is quite tricky.