I think the Deep Analysis / requiredBandwidths issue was resolved in 1.24 and higher.
- (Analysis) Bitrate analysis was sometimes incorrect when file contained image attachments (#12882)
The sample .flac you sent includes an image attachment.
I tested with 1.23.6. Deep Analysis of your sample file results in this:
<Media id="407809" duration="458706" bitrate="863" audioChannels="2" audioCodec="flac" container="flac">
<Part accessible="1" exists="1" id="434976" key="/library/parts/434976/1628546301/file.flac" duration="458706" file="/path/to/file.flac" size="51386717" container="flac" deepAnalysisVersion="4" hasThumbnail="1" requiredBandwidths="2147483647,2147483647,2147483647,2147483647,2147483647,2147483647,2147483647,2147483647">
<Stream id="965134" streamType="2" selected="1" codec="flac" index="0" channels="2" bitrate="863" albumGain="-7.32" albumPeak="0.950775" albumRange="4.149579" audioChannelLayout="stereo" bitDepth="16" endRamp="-16.66 0.11;-14.54 0.31;-10.72 8.61;-8.54 11.11;-5.63 12.41;-1.67 15.81;0.09 15.91;3.33 16.31;6.29 27.01;" gain="-7.32" loudness="-10.68" lra="4.15" peak="0.950775" requiredBandwidths="860,860,860,860,860,860,860,860" samplingRate="44100" startRamp="-51.00 0.00;-39.91 2.70;-29.81 5.30;-23.81 6.60;-20.64 7.00;-17.60 7.50;-14.78 8.40;-11.56 10.00;-8.60 10.60;-5.78 20.00;-2.99 25.00;0.21 31.60;3.20 37.50;6.25 57.20;" displayTitle="FLAC (Stereo)" extendedDisplayTitle="FLAC (Stereo)"> </Stream>
In particular, the Part requiredBandwidths values are wrong.
With 1.24, it now produces accurate data.
<Media id="407809" duration="458706" bitrate="863" audioChannels="2" audioCodec="flac" container="flac">
<Part accessible="1" exists="1" id="434976" key="/library/parts/434976/1628546301/file.flac" duration="458706" file="/path/to/file.flac" size="51386717" container="flac" deepAnalysisVersion="5" hasThumbnail="1" requiredBandwidths="3023,3023,3023,3023,3023,3023,3023,3023">
<Stream id="965134" streamType="2" selected="1" codec="flac" index="0" channels="2" bitrate="863" albumGain="-7.32" albumPeak="0.950775" albumRange="4.149579" audioChannelLayout="stereo" bitDepth="16" endRamp="-16.66 0.11;-14.54 0.31;-10.72 8.61;-8.54 11.11;-5.63 12.41;-1.67 15.81;0.09 15.91;3.33 16.31;6.29 27.01;" gain="-7.32" loudness="-10.68" lra="4.15" peak="0.950775" requiredBandwidths="860,860,860,860,860,860,860,860" samplingRate="44100" startRamp="-51.00 0.00;-39.91 2.70;-29.81 5.30;-23.81 6.60;-20.64 7.00;-17.60 7.50;-14.78 8.40;-11.56 10.00;-8.60 10.60;-5.78 20.00;-2.99 25.00;0.21 31.60;3.20 37.50;6.25 57.20;" displayTitle="FLAC (Stereo)" extendedDisplayTitle="FLAC (Stereo)">
After upgrading it might be enough to wait; I think Plex will see the “old” deepAnalysisVersion and upgrade analysis during maintenance.
Or you could Dance all of the files.
Or I searched my database for items with 2147483647 and forced a refresh for them manually.