[Environments:]
Windows10

baseline:
http://ftp.mozilla.org/pub/firefox/candidates/75.0b9-candidates/build1/partner-repacks/yandex/yandex-ru/v1/win64/ru/
region: RU

modern-configuration
Nightly 77.0a1 -ru build 20200503
region: RU
simulated distribution ini code: yandex-drp

Steps to reproduce:
Perform a simple search in the address bar by using the default search engine.

Actual result:
The resulted URL contains the following string: "clid=2186621&clid=2039342"

Expected result:
The search code for Yandex-drp is: "clid to 2039342", so I assume it should contain only "clid=2039342".

For yandex-planb distribution (ru locale, RU region), the search code is "clid=2186621&clid=1857376".

For yandex-portals distribution (ru locale, RU region), the search code is "clid=2186621&clid=1923034".

For yandex-ru distribution (ru locale, RU region), the search code is "clid=2186621&clid=1923018".

For yandez-ru-mz distribution (ru locale, RU region), the search code is "clid=2186621&clid=2320519".

For yandex-tr distribution (tr locale, TR region), the search code is "clid=2186621&clid=1953197".

For yandex-tr-gezginler distribution (tr locale, TR region), the search code is "clid=2186621&clid=1945716".

For yandex-tr-tamindir distribution (tr locale, TR region), the search code is "clid=2186621&clid=1945686".

Verified again with different scenarios and the search codes are correct for each yandex distribution.
78.0a1 Nightly 2020-05-07 & Win 10 64-bit

https://hg.mozilla.org/mozilla-central/rev/f7af137f976c

Marking as verified based on comment 9.
Also retested yandex-drp distribution with latest Nightly and the search code is correct.