Hard links on Windows client cause repeat rehashing of files (empty Phash)

client
1

I have freed up ~60GB on a Windows client by hard linking similar files (NTFS).
Now when the backup runs, it seems they are always reread/rehashed.

I don’t know if it’s related, but the log looks like this:
05/03/20 06:10 DEBUG Phash for id 108118 is wA4s/IC0ltvt3K+ozzGEty0ji9GPhTbaNcTkyS2nxRTdY+B3l/bBG56djXAfIropHmQP2pYwlmdR8tIKxJyuOQ–
05/03/20 06:10 DEBUG Phash for id 108119 is
05/03/20 06:11 DEBUG Phash for id 108124 is SrHxBPMJB9ZCrmwmKBzWxvKACGCgXoYy6nO8R5K7TYAqS8FxVjpW9PbPZCC+YqfsaWU5OoBUIIiV/bc1QnLpLQ–
05/03/20 06:11 DEBUG Phash for id 108125 is
05/03/20 06:12 DEBUG Phash for id 108164 is
05/03/20 06:12 DEBUG Phash for id 108182 is
05/03/20 06:12 DEBUG Phash for id 108191 is tbLldq/CNf9dsR52LWq5ngHWuLJkrMpEwOd0x7k+4wlaTlourYorTa6WwE/m3NWf9Nve1Td3372BsVSgnhjUFA–
05/03/20 06:12 DEBUG Phash for id 108192 is
05/03/20 06:12 DEBUG Phash for id 108195 is
05/03/20 06:12 DEBUG Phash for id 108204 is
05/03/20 06:12 DEBUG Phash for id 108210 is
05/03/20 06:12 DEBUG Phash for id 108213 is tbLldq/CNf9dsR52LWq5ngHWuLJkrMpEwOd0x7k+4wlaTlourYorTa6WwE/m3NWf9Nve1Td3372BsVSgnhjUFA–
05/03/20 06:12 DEBUG Phash for id 108214 is
05/03/20 06:12 DEBUG Phash for id 108226 is
05/03/20 06:12 DEBUG Phash for id 108232 is
05/03/20 06:12 DEBUG Phash for id 110328 is

Client: 2.4.8-cbt beta
Server: 2.4.12

2

Update: today it didn’t seem to rehash the files anymore.
But the log still has plenty of empty Phash’es, which weren’t before the hard links were created.
05/05/20 06:09 DEBUG Phash for id 108130 is
05/05/20 06:09 DEBUG Phash for id 108132 is
05/05/20 06:09 DEBUG Phash for id 108134 is
05/05/20 06:09 DEBUG Phash for id 108136 is
05/05/20 06:09 DEBUG Phash for id 108139 is
05/05/20 06:09 DEBUG Phash for id 108140 is
05/05/20 06:09 DEBUG Phash for id 108144 is
05/05/20 06:09 DEBUG Phash for id 108158 is
05/05/20 06:09 DEBUG Phash for id 108164 is
05/05/20 06:09 DEBUG Phash for id 108182 is
05/05/20 06:09 DEBUG Phash for id 108192 is
05/05/20 06:09 DEBUG Phash for id 108195 is
05/05/20 06:09 DEBUG Phash for id 108204 is
05/05/20 06:09 DEBUG Phash for id 108210 is
05/05/20 06:09 DEBUG Phash for id 108214 is
05/05/20 06:09 DEBUG Phash for id 108226 is
05/05/20 06:09 DEBUG Phash for id 108232 is
05/05/20 06:09 DEBUG Phash for id 108236 is
05/05/20 06:09 DEBUG Phash for id 108238 is
05/05/20 06:09 DEBUG Phash for id 108239 is
05/05/20 06:09 DEBUG Phash for id 108241 is
05/05/20 06:09 DEBUG Phash for id 108243 is
05/05/20 06:09 DEBUG Phash for id 108245 is
05/05/20 06:09 DEBUG Phash for id 108246 is
05/05/20 06:09 DEBUG Phash for id 108248 is
05/05/20 06:09 DEBUG Phash for id 108250 is