Z fold charging with power bank

anyone notice z fold can't charge well with portable battery? i have 1 aukey basix pro 10,000mah..using c to c charge...sometimes z fold show fast charge..sometimes it goes normal charge..

thought my z fold 4 dont like it...bought another shargeek slim pro 130w...also notice same

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worst is, for aukey...after a while, it will stop charging..