panic when joining the server

[RestartFU]

my server is on commit 8b34c23

I tried to join my server with different versions, and it looks like it started happening on 970d29b

panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xc0000005 code=0x0 addr=0x0 pc=0x55c438]

goroutine 99 [running]:
github.com/df-mc/dragonfly/server/player.(*Player).DeathPosition(0x3fd3333333333333?)
C:/Users/Administrator/go/pkg/mod/github.com/df-mc/dragonfly@v0.8.2-0.20220819190209-8b34c2314dc4/server/player/player.go:865 +0xb8
github.com/df-mc/dragonfly/server/session.(*Session).parseEntityMetadata(0xc0003a7e00, {0xb4f140, 0xc000146840})
C:/Users/Administrator/go/pkg/mod/github.com/df-mc/dragonfly@v0.8.2-0.20220819190209-8b34c2314dc4/server/session/entity_metadata.go:110 +0x2022
github.com/df-mc/dragonfly/server/session.(*Session).ViewEntityState(0xc0003a7e00, {0xb4f140, 0xc000146840})
C:/Users/Administrator/go/pkg/mod/github.com/df-mc/dragonfly@v0.8.2-0.20220819190209-8b34c2314dc4/server/session/world.go:857 +0x45
github.com/df-mc/dragonfly/server/session.(*Session).ViewEntity(0xc0003a7e00, {0xb4f140?, 0xc000146840?})
C:/Users/Administrator/go/pkg/mod/github.com/df-mc/dragonfly@v0.8.2-0.20220819190209-8b34c2314dc4/server/session/world.go:42 +0xa88
github.com/df-mc/dragonfly/server/world.showEntity({0xb4f140, 0xc000146840}, {0xb53370, 0xc0003a7e00})
C:/Users/Administrator/go/pkg/mod/github.com/df-mc/dragonfly@v0.8.2-0.20220819190209-8b34c2314dc4/server/world/world.go:1143 +0x3d
github.com/df-mc/dragonfly/server/world.(*World).addViewer(0x0?, 0xc0007f2840, 0xc001274bd0)
C:/Users/Administrator/go/pkg/mod/github.com/df-mc/dragonfly@v0.8.2-0.20220819190209-8b34c2314dc4/server/world/world.go:1086 +0x21a
github.com/df-mc/dragonfly/server/world.(*Loader).Load(0xc001274bd0, 0x4)
C:/Users/Administrator/go/pkg/mod/github.com/df-mc/dragonfly@v0.8.2-0.20220819190209-8b34c2314dc4/server/world/loader.go:95 +0x12b
github.com/df-mc/dragonfly/server/session.(*Session).sendChunks(0xc0003a7e00)
C:/Users/Administrator/go/pkg/mod/github.com/df-mc/dragonfly@v0.8.2-0.20220819190209-8b34c2314dc4/server/session/session.go:370 +0xef
github.com/df-mc/dragonfly/server/session.(*Session).background(0xc0003a7e00)
C:/Users/Administrator/go/pkg/mod/github.com/df-mc/dragonfly@v0.8.2-0.20220819190209-8b34c2314dc4/server/session/session.go:336 +0x13b
created by github.com/df-mc/dragonfly/server/session.(*Session).handlePackets
C:/Users/Administrator/go/pkg/mod/github.com/df-mc/dragonfly@v0.8.2-0.20220819190209-8b34c2314dc4/server/session/session.go:295 +0x8a
exit status 2