When tapping to share via HCE, the sharing phone was simultaneously acting as an NFC reader — triggering an OS app-chooser dialog that blocked the share flow.

Root cause

enableForegroundDispatch(…, null, null) only intercepts the ACTION_TAG_DISCOVERED fallback tier. Any NFC-capable Android phone carries NDEF data, so Android evaluates ACTION_NDEF_DISCOVERED first — which the null filters left unguarded — and dispatched it to all installed apps that handle that MIME type, producing a chooser.

Fix

Pass explicit IntentFilter arrays to enableForegroundDispatch covering all three dispatch tiers:

private fun buildDispatchFilters(): Array<IntentFilter> {
    val ndefFilter = IntentFilter(NfcAdapter.ACTION_NDEF_DISCOVERED).apply {
        try { addDataType("*/*") } catch (_: IntentFilter.MalformedMimeTypeException) {}
    }
    return arrayOf(
        ndefFilter,                                        // tier 1: any NDEF content
        IntentFilter(NfcAdapter.ACTION_TECH_DISCOVERED),   // tier 2: tech-routed tags
        IntentFilter(NfcAdapter.ACTION_TAG_DISCOVERED),    // tier 3: catch-all
    )
}

All three tiers now route to ShareActivity.onNewIntent where they are silently discarded. enableForegroundDispatch is intentionally used over enableReaderMode, which per Android docs disables HCE/CE routing for its entire active duration.