First off, hello to everyone. We've been lurkers here for years learning from the wealth of info in these forums. We've found many an answer we needed here.
Thanks to everyone who chimes in.

We've scoured the pages for the answer to this question, but haven't come across it, so here goes!

This is our first year using a steam tray with our bottler. It is the CDL hobby version propane fired bottler. We've used the bottler itself for two years without a steam tray. Before the steam tray, we heated the syrup slowly to avoid hot spots that form nitre. We never had any issue--the syrup was always crystal clear. But in the name of being able to do things faster, we invested in a steam tray. Under the impression that it eliminated the potential for nitre-forming hot spots, we opened up the burner and heated the syrup as quickly as possible. When the temp got up to 184, we turned the heat way down and bottled. The syrup was crystal clear when we bottled it, but the next day when I went down to take some pictures, I noticed that all of the bottles--from the first that I bottled at 184 to the last that I bottled (the thermometer never read over 188) all had flecks of what seems to be nitre in them. Some had settled to the bottom, others floating in the syrup. The only explanation we can come up with is that someplace the syrup must have reached a higher temp than the thermometer read. But can that even happen with a steam pan if the thermometer is reading right and never read higher than 188?

A bit of backstory in case it helps:
We take the syrup off the evaporator a little heavy and filter it through a CDL vacuum filter while still hot.
The syrup was around 60 degrees or so when I adjusted the density.
We brought the adjusted syrup up to temp on the bottler--started bottling at 184. Once we got it to temp, it was a longish bottling session because we were doing a lot of smaller bottles. There were 9 gallons of syrup in the bottler at the start.
I wasn't sure if it was nitre or sugar crystals that we were seeing, so I opened a bottle to test. No sugary feeling to the syrup. I did test the density, and it was about one full number heavy on the hydrometer. I've read since that we should be sure to shake the condensation on the lid back into the syrup during the bottling process.

We look forward to hearing what you all have to say!