Hey @Bill_Rowe!! Welcome to the community!!
It's not 100% clear to me exactly where this issue is occurring, but it's possible that you could reach out to Simba / whomever manages your Impala instance (or the vendor who provided it) for assistance!
If I were to guess, it seems an awful lot like the Connect instance does not trust the SSL certificate used for connection. However, for it to be intermittent suggests that that is almost certainly not the case
Are you intermittently seeing this issue on RSP, RSC, or both? Do you have any thoughts on how frequently the issue crops up? Or how the Shiny application is configured?
I have seen issues with apps that have MinProcesses >= 1 because the database connection can be left open for a very long time. It would be good to get a sense for whether that is the issue or not.
One other thing - while we do not support this JDBC driver, RStudio does have Professional ODBC drivers that can be used for free with our professional product stack. It may be worth switching this over to use the odbc package and the RStudio Pro Drivers, and then you would be covered under our support agreement for the professional drivers!
https://docs.rstudio.com/pro-drivers/