"ACKed segment that wasn't captured", but also "This is an ACK to the segment in frame: nnn".

edit

On Wireshark Version 4.0.1 (v4.0.1-0-ge9f3970b1527).

I have a lot of packets in a capture marked "ACKed segment that wasn't captured (common at capture start)", but also "This is an ACK to the segment in frame: nnn". Does this make sense?

I'd prepared a screen capture showing this but I'm forbidden to upload it due to lack of points. Sorry. Here's a packet export instead:

Frame 116064: 54 bytes on wire (432 bits), 54 bytes captured (432 bits)
Ethernet II, Src: 00:00:00_00:00:00 (00:00:00:00:00:00), Dst: 00:00:00_00:00:00 (00:00:00:00:00:00)
Internet Protocol Version 4, Src: 10.27.187.1, Dst: 10.22.61.4
Transmission Control Protocol, Src Port: 62326, Dst Port: 5018, Seq: 3345995, Ack: 3916774, Len: 0
    Source Port: 62326
    Destination Port: 5018
    [Stream index: 5]
    [Conversation completeness: Incomplete (12)]
    [TCP Segment Len: 0]
    Sequence Number: 3345995    (relative sequence number)
    Sequence Number (raw): 4121653282
    [Next Sequence Number: 3345995    (relative sequence number)]
    Acknowledgment Number: 3916774    (relative ack number)
    Acknowledgment number (raw): 80821650
    0101 .... = Header Length: 20 bytes (5)
    Flags: 0x010 (ACK)
    Window: 8192
    [Calculated window size: 8192]
    [Window size scaling factor: -1 (unknown)]
    Checksum: 0xd45b [unverified]
    [Checksum Status: Unverified]
    Urgent Pointer: 0
    [Timestamps]
    [SEQ/ACK analysis]
        [This is an ACK to the segment in frame: 116013]
        [The RTT to ACK the segment was: 0.010588000 seconds]
        [TCP Analysis Flags]
            [Expert Info (Warning/Sequence): ACKed segment that wasn't captured (common at capture start)]
                [ACKed segment that wasn't captured (common at capture start)]
                [Severity level: Warning]
                [Group: Sequence]

Frame 116013: 108 bytes on wire (864 bits), 62 bytes captured (496 bits)
Ethernet II, Src: 00:00:00_00:00:00 (00:00:00:00:00:00), Dst: 00:00:00_00:00:00 (00:00:00:00:00:00)
Internet Protocol Version 4, Src: 10.22.61.4, Dst: 10.27.187.1
Transmission Control Protocol, Src Port: 5018, Dst Port: 62326, Seq: 3916720, Ack: 3345995, Len: 54
    Source Port: 5018
    Destination Port: 62326
    [Stream index: 5]
    [Conversation completeness: Incomplete (12)]
    [TCP Segment Len: 54]
    Sequence Number: 3916720    (relative sequence number)
    Sequence Number (raw): 80821596
    [Next Sequence Number: 3916774    (relative sequence number)]
    Acknowledgment Number: 3345995    (relative ack number)
    Acknowledgment number (raw): 4121653282
    0101 .... = Header Length: 20 bytes (5)
    Flags: 0x018 (PSH, ACK)
    Window: 32736
    [Calculated window size: 32736]
    [Window size scaling factor: -1 (unknown)]
    Checksum: 0x0488 [unverified]
    [Checksum Status: Unverified]
    Urgent Pointer: 0
    [Timestamps]
    [SEQ/ACK analysis]
        [This is an ACK to the segment in frame: 116010]
        [The RTT to ACK the segment was: 0.000249000 seconds]
        [Bytes in flight: 54]
        [Bytes sent since last PSH flag: 54]
        [TCP Analysis Flags]
            [Expert Info (Warning/Sequence): ACKed segment that wasn't captured (common at capture start)]
                [ACKed segment that wasn't captured (common at capture start)]
                [Severity level: Warning]
                [Group: Sequence]
    TCP payload (54 bytes)