odd Table rate shipping module showing default lang file vs template file

Not sure I will get any answers as I am not really sure why or what is happening - however I thought that I would ask in case anyone knows where else to check

So shop getting ~20 orders per day

for 5 orders the shipping module (table rate) defaulted to the language file within the default ENGLISH directory verses the MYTEMPLATE directory

we also had 1 order come through using the storepickup module that did the same

To avoid this I have edited the ENGLISH language file to match the MYTEMPLATE file - but I believe that is the wrong thing as it should only ever use the MYTEMPLATE files unless none are there..?

Any idea why it did this for those handful of orders?

checked that all use same shipping/zone/tax settings etc

I wondered if slow server at that time and it couldn't get access to that MYTEMPLATE folder maybe? Could that happen?

Any other thoughts or things that I can check - as it was very obvious when it happened!

as it said
Table Rate (Best Way):
instead of
Shipping (Once your order is Completed, it will be shipped via Courier (or Royal Mail if your order value was under £10).):

Kind of obvious

Really just looking for how it could happen to try to stop it in the future

Thanks
Sarah

Reasons why ZC might not use an overridden language file:

a) the override file doesn't exist, so it uses the default
b) the override "folder" doesn't exist or is being renamed
c) the template selector in the Admin is being used to choose different templates for which no matching overrides exist ... even temporarily
d) the customer has been shopping in a different language, with different/missing overrides
e) modifications to the core templating and language system, either by the storeowner, an unauthorized intruder, or a plugin
f) fileserver permissions/ownership problems causing the override files to not be readable for that moment in time

Thank you for your reply - I believe that its only the last option that might have done it .. anyway I will keep an eye on it as everything else you have mentioned I have checked upon