Unable to save an email Channel template using custom HTML code

Your software
My Mautic version is:v4.4.9
My PHP version is: 7.4.33
My Database type and version is: percona-server:5.7

Your problem
My problem is: I’ve been able to save this template, but an included URL of an .ics file within a mailto: link is cut short in Outlook (due to white space in the file name requiring encoding). When fixes are made to allow this URL to appear completely, Mautic won’t allow me to save the template, clicking "Save & Close” just greys out and no further progress can be made or saved, even when reverted. The HTML has been tested in other environments and functions correctly, so is there anything which Mautic may be blocking that would ordinarily function?

Snippet of Mailto code that allows me to save:

href="mailto:?subject=Confluence%2FJira%20Office%20Hours%20Call%20Reminder&body=Hi%20all%2C%0A%0AJust%20a%20quick%20reminder%20that%20the%20next%20Confluence%2FJira%20Office%20Hours%20is%20coming%20up%20on%20[Insert meeting date here].%20Don’t%20forget%20to%20add%20it%20to%20your%20calendars%20and%20get%20along%20if%20you%20can.%20Click%20here%20to%20add%20it%20to%20your%20calendar%20as%20a%20reminder%3A%20https%3A%2F%2Fconfluence.optum.com%2Fdownload%2Fattachments%2F76064065%2FConfluenceJIRA%20Office%20Hours%20-%20Hosted%20by%20DMS%20%282nd%20Wednesday%20of%20the%20Month%29.ics%3Fversion%3D1%26modificationDate%3D1690830880236%26api%3Dv2%0A%0A%5BInsert%20your%20sign%20off%20here%5D

the lines with below is the link that displays but does not contain the full link: https%3A%2F%2Fconfluence.optum.com%2Fdownload%2Fattachments%2F76064065%2FConfluenceJIRA%20Office%20Hours%20-%20Hosted%20by%20DMS%20%282nd%20Wednesday%20of%20the%20Month%29.ics%3Fversion%3D1%26modificationDate%3D1690830880236%26api%3Dv2

Snippet of Mailto code that does NOT allow me to save:

mailto:?subject=Confluence%2FJira%20Office%20Hours%20Call%20Reminder&body=Hi%20all%2C%0A%0AJust%20a%20quick%20reminder%20that%20the%20next%20Confluence%2FJira%20Office%20Hours%20is%20coming%20up%20on%20[Insert meeting date here].%20Don’t%20forget%20to%20add%20it%20to%20your%20calendars%20and%20get%20along%20if%20you%20can.%20Click%20here%20to%20add%20it%20to%20your%20calendar%20as%20a%20reminder%3A%20<https%3A%2F%2Fconfluence.optum.com%2Fdownload%2Fattachments%2F76064065%2FConfluenceJIRA%2520Office%2520Hours%2520-%2520Hosted%2520by%2520DMS%2520%25282nd%2520Wednesday%2520of%2520the%2520Month%2529.ics%3Fversion%3D1%26modificationDate%3D1690830880236%26api%3Dv2>%0A%0A%5BInsert%20your%20sign%20off%20here%5D

Difference with this and the snippet that does save is:

  1. the < > closing the link
  2. adding %2520 instead of just the %20

<https%3A%2F%2Fconfluence.optum.com%2Fdownload%2Fattachments%2F76064065%2FConfluenceJIRA%2520Office%2520Hours%2520-%2520Hosted%2520by%2520DMS%2520%25282nd%2520Wednesday%2520of%2520the%2520Month%2529.ics%3Fversion%3D1%26modificationDate%3D1690830880236%26api%3Dv2>

These errors are showing in the log:
Log doesn’t identify error specific to not saving. Log displays below (not sure if this is related):

[2024-01-19 06:34:16] mautic.ERROR: STAT UPDATE: cURL error 35: OpenSSL SSL_connect: Connection reset by peer in connection to updates.mautic.org:443 (see libcurl - Error Codes) for https://updates.mautic.org/stats/send {“hostname”:“8afac79a827b”,“pid”:669}
[2024-01-19 06:34:16] mautic.ERROR: UPDATE CHECK: cURL error 35: OpenSSL SSL_connect: Connection reset by peer in connection to api.github.com:443 (see libcurl - Error Codes) for https://api.github.com/repos/mautic/mautic/releases {“hostname”:“8afac79a827b”,“pid”:669}

Steps I have tried to fix the problem:

Tried to isolate the issue by replacing the snippets with one that works and one with the recent changes (that does not save). The later set of code has been tested in other environments and results as expected.

Any help or insight would be greatly appreciated