G1 gc 0 SoftReference but cost more than 1s

Question

G1 YGC cost 4s, here is the log:

2024-05-15T19:53:02.107+0800: 77871.126: [GC pause (G1 Evacuation Pause) (young)
2024-05-15T19:53:02.139+0800: 77871.159: [SoftReference, 0 refs, 3.3403409 secs]
2024-05-15T19:53:05.479+0800: 77874.499: [WeakReference, 1 refs, 0.0007746 secs]
2024-05-15T19:53:05.480+0800: 77874.500: [FinalReference, 8190 refs, 0.0021828 secs]
2024-05-15T19:53:05.482+0800: 77874.502: [PhantomReference, 18 refs, 51 refs, 0.0069966 secs]
2024-05-15T19:53:05.489+0800: 77874.509: [JNI Weak Reference, 0.0001143 secs], 3.3885878 secs]
                                         [Parallel Time: 31.0 ms, GC Workers: 8]
                                         [GC Worker Start (ms): Min: 77871127.5, Avg: 77871127.6, Max: 77871127.7, Diff: 0.2]
                                         [Ext Root Scanning (ms): Min: 4.3, Avg: 4.8, Max: 6.1, Diff: 1.8, Sum: 38.3]
                                         [Update RS (ms): Min: 17.8, Avg: 18.9, Max: 19.3, Diff: 1.5, Sum: 151.2]
                                         [Processed Buffers: Min: 72, Avg: 92.1, Max: 103, Diff: 31, Sum: 737]
                                         [Scan RS (ms): Min: 0.2, Avg: 0.4, Max: 0.6, Diff: 0.4, Sum: 3.6]
                                         [Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.1]
                                         [Object Copy (ms): Min: 6.2, Avg: 6.4, Max: 6.6, Diff: 0.4, Sum: 51.2]
                                         [Termination (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
                                         [Termination Attempts: Min: 1, Avg: 2.6, Max: 5, Diff: 4, Sum: 21]
                                         [GC Worker Other (ms): Min: 0.1, Avg: 0.1, Max: 0.2, Diff: 0.2, Sum: 1.2]
                                         [GC Worker Total (ms): Min: 30.5, Avg: 30.7, Max: 30.8, Diff: 0.3, Sum: 245.5]
                                         [GC Worker End (ms): Min: 77871158.2, Avg: 77871158.3, Max: 77871158.4, Diff: 0.2]
                                         [Code Root Fixup: 0.1 ms]
                                         [Code Root Purge: 0.0 ms]
                                         [Clear CT: 0.9 ms]
                                         [Other: 3356.5 ms]
                                         [Choose CSet: 0.0 ms]
                                         [Ref Proc: 3350.7 ms]
                                         [Ref Enq: 0.3 ms]
                                         [Redirty Cards: 0.4 ms]
                                         [Humongous Register: 0.1 ms]
                                         [Humongous Reclaim: 0.0 ms]
                                         [Free CSet: 2.3 ms]
                                         [Eden: 4836.0M(4836.0M)->0.0B(332.0M) Survivors: 76.0M->76.0M Heap: 7108.9M(8192.0M)->2273.2M(8192.0M)]
                                         Heap after GC invocations=1862 (full 0):  garbage-first heap   total 8388608K, used 2327784K [0x00000005e0800000, 0x00000005e0c04000, 0x00000007e0800000)   region size 4096K, 19 young (77824K), 19 survivors (77824K)  Metaspace       used 236360K, capacity 255086K, committed 255232K, reserved 1275904K   class space    used 25725K, capacity 29171K, committed 29184K, reserved 1048576K }
                                         [Times: user=0.28 sys=0.02, real=3.39 secs] 

There is 0 SoftReference, but cost 3.3403409 secs, why? How can I solve it?