Had the same experience but even worse with a boat
purchased a year ago. The bronze
raw water strainer broke as I tried (gently) to open it for inspection
Closing all seacocks when away is the absolutely right practice even with my fully replaced 11 Trudesign seacocks, fittings and plumbing
I removed all bronze
raw water strainers (refrigerators, a/c) and replaced with over the waterline plastic strainers. Yes, I had to also replace the pumps to self priming, but this is a major safety
concern. I do not trust strainers and pumps below the waterline.