JSON generated from project using step template incorrect

I updated to OD 2020.4.2 a few weeks ago, and last Friday attempted to create a new Project using a custom IIS deployment step I’ve had around for years.
The deployment failed, and after a lot of troubleshooting I discovered that rather than the step-template provided JSON of

"Octopus.Action.IISWebSite.Bindings": "[{\"protocol\":\"http\",\"ipAddress\":\"#{HTTPIP}\",\"port\":80,\"host\":\"#{Hostname}\",\"thumbprint\":null,\"certificateVariable\":null,\"requireSni\":false,\"enabled\":true},{\"protocol\":\"https\",\"ipAddress\":\"#{HTTPIP}\",\"port\":\"443\",\"host\":\"#{Hostname}\",\"thumbprint\":\"#{SSLThumbprint}\",\"certificateVariable\":\"\",\"requireSni\":\"True\",\"enabled\":true},{\"protocol\":\"http\",\"ipAddress\":\"#{HTTPIP2}\",\"port\":\"80\",\"host\":\"#{Hostname2}\",\"thumbprint\":null,\"certificateVariable\":null,\"requireSni\":false,\"enabled\":\"#{if EnableBinding2}true#{/if}#{unless EnableBinding2}false#{/unless}\"} etc

it was instead using
"Octopus.Action.IISWebSite.Bindings": "[{\"protocol\":\"http\",\"port\":\"80\",\"host\":\"\",\"thumbprint\":null,\"certificateVariable\":null,\"requireSni\":\"False\",\"enabled\":\"True\"}]",

None of the other projects using this step template exhibited this problem despite being on the same version.
The amount of data gathering I was able to do was minimal due to trying to fix the issue - eventually adding a dummy line to the step template, then deleting it, then updating my project to this latest (effectively identical) version appears to have resolved it for this particular project at this time.

Hi Chris,

Thanks for getting in touch! That certainly looks like the incorrect behavior and it sounds like you’ve stumbled into some bug somewhere here. I’ve seen an issue kind of similar in the past involving a fairly big upgrade affecting an IIS step that is quite old, which was to do with the upgrade scripts handling some old data, and modifying/re-saving it was a workaround.

Could you let me know which version you upgraded from? How old roughly is this specific project and step? I imagine the way you’ve resolved this should permanently fix it (assuming it’s related to the previously mentioned bug), but I’d be very interested to hear if it pops up again.

I look forward to hearing back!

Best regards,

Kenny

The audit log doesn’t appear to show version upgrades (suggestion!) but other info shows it would have been v2020.3.6 installed ~Sept 23.
The step template has been around since at least Jan 2018 in some form or other, and hadn’t been edited since at least April of this year. The project was brand new last week.

Hi Chris,

Thank you for following up. This issue definitely does sound very similar, though the fact that it worked for others while on the same version is different from what I’ve experienced in my previous repro. My guess is what you’ve already done should be a permanent fix, but if you do hit this again please let us know and we can dive into it.

Best regards,

Kenny