RN516 - Frontview -- appcache?

Occasionally my frontView wedges itself.

reloads of the admin endpoint at https://192.168.1.17/admin/ simply result in the splash page, with the version number displayed after a moment (6.1.4).

Looking in Chrome's developer console, I see this message:

Application Cache Error event: Manifest fetch failed (-1) https://192.168.1.17/admin/appcache_1.0.2.51.appcache 

if I directly access that URL, I get:

CACHE MANIFEST 
CACHE: 
./frontview_1.0.2.51.js 
./ldMachine\jobs\R6UI-6.1.x\workspace\_gen2flat\trunk\builder\trunk\_deploy\css\browse_1.0.2.51_base64.css 
./ldMachine\jobs\R6UI-6.1.x\workspace\_gen2flat\trunk\builder\trunk\_deploy\css\frontview_1.0.2.51_base64.css 
./ldMachine\jobs\R6UI-6.1.x\workspace\_gen2flat\trunk\builder\trunk\_deploy\css\wizard_1.0.2.51_base64.css 
./ldMachine\jobs\R6UI-6.1.x\workspace\_gen2flat\trunk\builder\trunk\_deploy\extjs\ext-all.js 
./ldMachine\jobs\R6UI-6.1.x\workspace\_gen2flat\trunk\builder\trunk\_deploy\extjs\adapter\ext\ext-base.js 
NETWORK: 
* 

Is that normal? Im wondering if I need to somehow refresh this app cache? The only app i've got installed is plex:

# ll /apps/
total 0
drwxr-xr-x 1 root  root   52 Oct 22 02:00 APPGENIE
dr-xr-xr-x 1 root  root    0 Oct 21 21:57 DO_NOT_DELETE
drwxr-xr-x 1 admin admin 432 Nov  2 13:50 plexmediaserver

Thanks

-Mark