What browser is this? I can't reproduce.

I.e., see mrubinsk.blogspot.com for an example of a kronolith calendar 
displaying fine from my personal domain.

There is a problem with embed calendar from horde using generated 
javascript code. Since web browsers implemented "Blocking the load of 
cross-origin, parser-blocking scripts inserted via document.write in 
the main frame? on slow networks we have got the following errors:

A Parser-blocking, cross-origin script, 
http://horde.something.pl/horde/js/prototype.js, is invoked via 
document.write. This may be blocked by the browser if the device has 
poor network connectivity.
embed?token=orqlGpq11UGPddSMPIucwA8&calendar=internal_aB6L3ktKWt3jNzaUgbtJuQ1&container=kronolithCa?:7
A Parser-blocking, cross-origin script, 
http://horde.something.pl/horde/js/tooltips.js, is invoked via 
document.write. This may be blocked by the browser if the device has 
poor network connectivity.
embed?token=orqlGpq11UGPddSMPIucwA8&calendar=internal_aB6L3ktKWt3jNzaUgbtJuQ1&container=kronolithCa?:11
A Parser-blocking, cross-origin script, 
http://horde.something.pl/horde/kronolith/js/embed.js, is invoked via 
document.write. This may be blocked by the browser if the device has 
poor network connectivity.

The solution may be to load scripts asynchronously using 
<!--a75c305b1c0a6022--><script src="..." async> or 
element.appendChild().

We noticed that the newest version of horde still have the problem.