Status update:
I sent the strobes to Tusa. Prior to doing so, they said to expect a 3–5 day timeframe for evaluation upon receipt. 7 business days later, I hadn't heard anything, so I called and got a VM. I emailed the tech and never got a response. I called on day 8 and they answered.
The typical conversation goes something like this: If your strobes have ever flooded, then a repair won't be covered under warranty. I then confidently express that they have never been flooded. They respond in kind that they will inspect it for flood damage very closely, specifically under the leads on the cap. I then insist again that they've never been flooded.
Then it's confusion over what's wrong with them, which camera I use, which batteries I use, etc. etc. etc. Finally satisfied with my responses, they promised on day 8 to look at them that day.
A few hours later, I received a call from the tech. He said I was right, there wasn't any flooding, and the strobes are behaving exactly how I described. He then said his manager approved sending out replacement refurbished strobes.
I asked what was wrong with them and got some vague answers where the focus turned back to what kind of batteries I use (Eneloop and Eneloop Pros). Even though he uses the SAME batteries, he asked me for the mah values on the batteries. He said good, never use batteries over 2500 mah (which is what the pros are exactly).
Of note, the original strobe to fail, failed using the standard Eneloop batteries. I bought the pros after reading about aging batteries being a problem (my originals were only 1.5 years old). The second strobe died using the pros.
It's now been several days since being told they will ship refurbished strobes to me. I haven't received any sort of communication or tracking number. So now I'm going to have to call again to get an update.
In the end, if this is the level of service Sea & Sea offers to US customers, through a 3rd party Tusa, I've lost confidence in their ability to support their products efficiently. We live in a world where technology can automate the simplest things, like the communication of receipt of returned products, status updates to a repair, and even tracking numbers. I feel like it's 1990 and I have to make phone calls which takes time away from the tech.