Describe the issue

ublock unhides hidden elements when it's updated

One or more specific URLs where the issue occurs

tumblr.com/dashboard

Screenshot in which the issue can be seen

[pending ublock update]

Steps for anyone to reproduce the issue

1. put something like www.tumblr.com##.post[data-is_recommended="1"] in your custom filters
2. go on a page with such elements
3. wait for ublock to update

Your settings

set:

• hide placeholders
• show blocked count
• use context menu
• advanced mode
• no prefetch
• no auditing

unset:

• everything else?

• OS/version: arch linux x86_64
• Browser/version: firefox 56.0.1
• uBlock Origin version: 1.14.17b9

Your filter lists

all ublock
easylist
adblock warning removal
easyprivacy
malware domain list
malware domains
fanboy's annoyance
fanboy's social
peter lowe's ad/tracking list
aaklist (which is apparently "custom"?)

Your custom filters (if any)

! 2017-04-19, 12:18:23 PM https://uk.pinterest.com/autisticmind/drawings/
uk.pinterest.com##div:nth-of-type(3) > div:nth-of-type(3)

! 2017-05-03, 5:43:42 PM https://www.tumblr.com/dashboard
www.tumblr.com##.post[data-is_recommended="1"]

||belarr.com/bakercat/
||belarr.com/bakercat/$document

! 2017-08-16, 12:27:28 AM https://www.tumblr.com/dashboard
www.tumblr.com##.chat-status-banner

! 2017-08-16, 12:27:45 AM https://www.tumblr.com/dashboard
www.tumblr.com##.status-indicator

! 9/24/2017, 12:30:08 PM https://www.tumblr.com/dashboard
! www.tumblr.com##.post:has(.recommendation-reason-link)
!

! speedtest stuff
@@/hello^$xmlhttprequest,domain=speedtest.net
@@/ping^$xmlhttprequest,domain=speedtest.net
@@/download^$xmlhttprequest,domain=speedtest.net
@@/upload^$xmlhttprequest,domain=speedtest.net

edit: I believe this can be fixed with startup hooks: https://developer.mozilla.org/en-US/Add-ons/WebExtensions/API/runtime/onInstalled (but I'm not an extension developer)