Incorrect data for selected Previous and current periods

Jdokken , In case you have a standard period/month you should use time intelligence,

Else create a separate period column, with one of the column is YYYYPP , the create a rank column on that

new column
Period Rank = RANKX(all('Period'),'Period'[year period],,ASC,Dense)

measures

This Period = CALCULATE(sum('order'[Qty]), FILTER(ALL('Period'),'Period'[Period Rank]=max('Period'[Period Rank])))
Last Period = CALCULATE(sum('order'[Qty]), FILTER(ALL('Period'),'Period'[Period Rank]=max('Period'[Period Rank])-1))

Last Year Period = CALCULATE(sum('order'[Qty]), FILTER(ALL('Period'),'Period'[Period]=max('Period'[Period]) && 'Period'[Year]=max('Period'[Year])-1))

for standard one

Power BI — Month on Month with or Without Time Intelligence
https://medium.com/@amitchandak.1978/power-bi-mtd-questions-time-intelligence-3-5-64b0b4a4090e
https://www.youtube.com/watch?v=6LUBbvcxtKA