Unable to set html signature as persistent when using mobile phone t

[bencastan]

Using round cubemail 1.1.7
nginxx 1.62.
PHP 5.6.30-0+deb8u1 (cli) (built: Feb  8 2017 08:50:21)
psql
In a cluster of two hosts behind a load balancer on AWS.

When using a mobile phone to send emails I am unable tome the selection of HTML signatures persistent.
I can select 'always' and when clinking the sea button I get the saved response,
However all emails sent via mobile fail to have HTML signatures.
Searches on the forums etc. have not shown me any clear issues nor solutions.

And assistance or suggestions would be appreciated.