TYPO3 Core

To reproduce this error, please do these steps:

1) Setup a new "Root Page" with this TypoScript:

TS Constants:

aaaa = 222222
[globalVar = GP:L = 2]
aaaa = 111111
[global]

TS Setup:

[globalVar = TSFE:id = {$aaaa}]

[global]

page = PAGE
page.1 = TEXT
page.1.value = {$aaaa}

page.2 = TEXT
page.2.value = cachetest

2) Create two new "Website Language" records
3) Create a new page and translate it into these two alternative languages
4) Flush all caches
5) Logout from TYPO3 BE
6) Open page in first language in your browser (e.g. domain.local/?id=1&L=1) => TYPO3 generates cache for this page
7) Reload this page => TYPO3 serves page from cache
8) Open page in second language in your browser (e.g. domain.local/?id=1&L=2) => TYPO3 generates cache for this page
9) Reload this page several times => TYPO3 generates the page cache every reload!!
10) Look in your database in table cf_cache_pages, there should be two entries. The first entry has ID 1, the second entry has an ID > 2 (this depends on how often you had reloaded the page with second language).

Error occures in TYPO3 8.7.27
Tested with Ubuntu / Vagrant Box / PHP 7.1 / MySQL 5.6
Tested with Windows 7 / MAMP / PHP 7.2 / MySQL 5.7