That dependable hair mask failed me at the worst moment

I was at my sister's place in Nashville last month, getting ready for her friend's wedding. I had used the same shea butter mask for like two years, no issues. But that day, my hair came out feeling greasy and flat, not soft at all. I panicked because we had maybe 45 minutes before we needed to leave. I ended up re-washing with my regular shampoo twice and then using just a dab of leave-in from a travel bottle my sister had. It worked out okay in the end, but I have no idea why that mask failed me that time. Could it be the humidity down there, or does product sometimes just go bad without smelling off? Has anyone else had a trusted product randomly betray them on a big day?