I think that’s the percent of copper that you used seems high. I pour almost all of my golds, yellows, whites and rose. I never quench in ingot but I do forge them first. I use a 14k rose from AAA in Portland OR. Don’t often have cracking issues. I draw wire from ingots or roll flat sheet. And forge rings. Maybe the high amount of copper can be reduced in your next try.
Best of luck.
Andy
Please excuse any typos-- curse my clumsy digits…