Importing an Email into an Opportunity creates a blank archive email record

Hi,
We’re trialling SuiteCRM, so far it looks suitable for us and I’m happy.

One thing I wanted to do is be able to import emails from an IMAP folder manually. (I don’t want full automation for various reasons.)

I’ve successfully created my user email connection and this can fetch my mail via IMAP (Gmail)
I created a clients/CRM folder in IMAP which I manually copy emails over into using my mail client that I want to import to CRM rather than copy/paste into notes against an opportunity.
This is done by setting the Monitored Folder as Clients/CRM

Problem 1: On 7.9.7 I saw only the email in this folder. I just upgraded to 7.9.9 and this is bringing back my default inbox and ignoring the Monitored Folder config.
If I remove the clients/CRM folder from the Monitored Folder field and click Select to choose a new one I get the warning “Errors were detected:
Monitored Folder is required.”
If I manually enter clients/CRM into this field and click Select I’m told “The following folder(s) clients/CRM either does not exist or has been deleted from server” - which isn’t true, but could explain why it’s defaulting back to the primary inbox.

Clicking Test Settings says everything is fine (incidentally the feedback box to tell me this appears off screen underneath the top menu?!)
I tried removing the email box config and re-adding it. This didn’t help the situation.

Problem 2:
If I click to view an email from the inbox I get a blank page, log reports:

Thu Jan 18 12:51:20 2018 [2787][1][FATAL] Exception handling in /var/www/crm/include/MVC/Controller/SugarController.php:402
Thu Jan 18 12:51:20 2018 [2787][1][FATAL] Exception in Controller: DateTime::createFromFormat (D, d M Y H:i:s O,): expected DateTime but it returned FALSE or empty.
Thu Jan 18 12:51:20 2018 [2787][1][FATAL] backtrace:
#0 /var/www/crm/modules/Emails/include/DetailView/EmailsNonImportedDetailView.php(82): InboundEmail->returnNonImportedEmail('80', '55636')
#1 /var/www/crm/modules/Emails/views/view.detailnonimported.php(72): EmailsNonImportedDetailView->populateBean(Array)
#2 /var/www/crm/include/MVC/View/SugarView.php(197): EmailsViewDetailNonImported->preDisplay()
#3 /var/www/crm/include/MVC/Controller/SugarController.php(432): SugarView->process()
#4 /var/www/crm/include/MVC/Controller/SugarController.php(375): SugarController->processView()
#5 /var/www/crm/include/MVC/SugarApplication.php(105): SugarController->execute()
#6 /var/www/crm/index.php(52): SugarApplication->execute()
#7 {main}

TimeZone is configured in PHP for Apache and CLI as date.timezone = “Europe/London”

Could it be the opening email process is looking for the email in the correct clients/CRM folder and not finding it, because it’s not there?

Problem 3:
When I could read an email in 7.9.7 and clicked to assign to an opportunity it just created a blank archived email with no content.
The situation was pretty much as this old post described: https://suitecrm.com/forum/installation-upgrade-help/16008-archive-email-leads
I note the SuiteCRM demo also shows the same issue - when adding an archive email it doesn’t give you any email details?

Ubuntu 16.04 running no other sites on this server.
mysql Ver 15.1 Distrib 10.0.33-MariaDB, for debian-linux-gnu (x86_64) using readline 5.2
Server version: Apache/2.4.18 (Ubuntu)
PHP 7.1.13-1+ubuntu16.04.1+deb.sury.org+1

Thanks in advance.