Mentioning how meeting with Mrs Thorpe had been the turnaround point in front of the Morlands sounds clueless for another reason. Considering how Isabella hurt and deceived James, it seems insensitive to bring the Thorpes up (and so happily!) in conversation with Catherine and Mrs Morland. Could Mrs Allen not know what happened? I don't think her visits are the type to take offence over that, but I would certainly feel that is a social faux-pas. I know Mrs Allen is not callous, yet it does seem to fit with her clueless demeanour.