4 sourced reports, with what to check before you buy. Each one links to the page it was reported on.
Costly or dangerous
Redmi Buds 6S repeated disconnection (断联) — 4 service visits, same fault, owner calls it a design defect
A consumer complaint on the Chinese 黑猫投诉 (Heimao) platform, filed against Xiaomi for the REDMI Buds 6S, reports repeated disconnection (断联), four service visits including repair and replacement, with the same fault recurring — the complainant says other buyers report the same problem and calls it a factory design defect.
What to check. This is the strongest signal of a recurring Bluetooth disconnection fault on the 6S. If you buy, test connection stability over days and keep proof of purchase; the complainant found Xiaomi service would not explain the fault and only offered paid replacement.
Redmi Buds 6S right earbud battery cell dead (1.89Ω internal resistance) — needs teardown to replace
A repair teardown on a Chinese repair forum shows the 6S battery cell is welded under the flex cable inside the stem, so replacing it requires opening the earbud stem and desoldering the nickel tabs; the owner measured the right earbud cell at 1.89Ω internal resistance (dead) and left at 900mΩ.
What to check. Battery life can collapse on one earbud and the cell is not user-replaceable — it is welded under the flex cable, so a dead cell means either a careful teardown/solder job or a warranty/service claim. Check battery health early, before the 1-year-ish warranty window closes.
Redmi Buds 6S left earbud battery life collapses from ~7h to ~45min after 8 months
A Vietnamese owner thread titled 'Redmi Buds 6s sụt pin tai trái từ 7h xuống 45'' (left earbud battery drops from 7h to 45') reports the left earbud's battery life collapsed after about 8 months of light use, and the poster warns that TWS battery life figures are not to be trusted.
What to check. Expect asymmetric battery ageing — one earbud can lose most of its runtime within months while the other still holds charge. If you buy, verify battery health early and prefer a unit with a service/warranty path, since the cell is not user-replaceable.
Redmi Buds 6S not selectable in Xiaomi app; uneven volume between earbuds
A Russian owner review of the Redmi Buds 6S (M2403E1) reports the model cannot be selected in the companion app (so it cannot be configured) and that volume differs between the two earbuds.
What to check. A firmware/app quirk: the 6S may not appear in the Xiaomi companion app, so EQ/controls may be unavailable and one earbud can be louder than the other. Low severity — it does not stop the buds working, but it limits configuration.
These reports come from the pages linked under each item: owner forums, repair guides and workshops. They are not a diagnosis of any one unit, and a careful check of the one you are buying still applies.
Text from the Kriko Wireless earbuds catalog, version 0.1.4, under the CC-BY-SA-4.0 license.
