Seafile server error "Failed to load commit json object: '[' or '{' expected near '?'"

I see these strange logs in seafile.log

[09/22/2020 06:09:54 AM] virtual-repo.c(866): Failed to get commit 2c45ddc4-10b9-47c1-8560-26a81a6fa990:bece4693.
[09/22/2020 06:09:54 AM] ../common/commit-mgr.c(837): Failed to load commit json object: '[' or '{' expected near '?'.
[09/22/2020 06:09:54 AM] virtual-repo.c(866): Failed to get commit 2c45ddc4-10b9-47c1-8560-26a81a6fa990:bece4693.
[09/22/2020 06:13:59 AM] ../common/commit-mgr.c(837): Failed to load commit json object: '[' or '{' expected near '?'.
[09/22/2020 06:13:59 AM] virtual-repo.c(866): Failed to get commit 2c45ddc4-10b9-47c1-8560-26a81a6fa990:bece4693.
[09/22/2020 06:13:59 AM] ../common/commit-mgr.c(837): Failed to load commit json object: '[' or '{' expected near '?'.
[09/22/2020 06:13:59 AM] virtual-repo.c(866): Failed to get commit 2c45ddc4-10b9-47c1-8560-26a81a6fa990:bece4693.

I ran

$ ./seaf-fsck.sh 2c45ddc4-10b9-47c1-8560-26a81a6fa990

Starting seaf-fsck, please wait ...

[09/21/20 13:21:59] fsck.c(590): Running fsck for repo 2c45ddc4-10b9-47c1-8560-26a81a6fa990.
[09/21/20 13:21:59] fsck.c(416): Checking file system integrity of repo Projects(2c45ddc4)...
[09/21/20 17:24:21] fsck.c(654): Fsck finished for repo 2c45ddc4.

seaf-fsck run done

Done.

But seems no result. Any idea how to resolve it?

Seafile Server Community 7.1.3, Ubuntu Server 18.04