My brother and I show up as full siblings (2310cM shared). He shows up to cousin #1 (thru our mother) 976cM shared and cousin #2 (thru our father) 813Cm shared. However, I share with cousin #1 920cM (similar) and Cousin #2 1724cM.
This means that cousin #2 shows up as either my first cousin or half sister (through our dad). This seems unusually high for a cousin and our dads were brothers. Could a 1st cousin have that high a match if the dads were brothers?