website config: ngx pagespeed css issues

[mef]

Following error did occur on Chrome:

css failed to load on https://mango-is.com/blog/convert/a-sublime-landing-page/, with error err_content_decoding_failed for the css file (file from ngx pagespeed cache, concatenating css).

Worked around by:

• disabling combine_css and rewrite_css filters
• downgrading ngx pagespeed module to 1.11.x instead of 1.12.x

(possibly, only the first modification was enough, with restart of the nginx service, instead of only reload, which was ineffective (plus clearing cache directory for affected site).

Probably related issue: apache/incubator-pagespeed-ngx#1346

Todo: Follow-up on mainstream issue's developments, test possible solutions...