I recently saw this on a node running master (90a5786bba4baac1c0270e1f4bf5bb8c790e10de iirc):
02024-09-23T13:12:14Z UpdateTip: new best=00000000000000000000d3ebbca24c44745cfa14153e758d29af82275e00c00f height=862523 version=0x20026000 log2_work=95.170324 tx=1084781037 date='2024-09-23T13:03:46Z' progress=0.999997 cache=302.1MiB(2120379txo)
12024-09-23T13:12:14Z UpdateTip: new best=0000000000000000000164dcfef37624f2cc6b177032bbca57631285c2cd0267 height=862524 version=0x20150000 log2_work=95.170337 tx=1084782848 date='2024-09-23T13:05:37Z' progress=0.999998 cache=302.4MiB(2117708txo)
22024-09-23T13:12:15Z New outbound-full-relay v1 peer connected: version: 70016, blocks=862524, peer=25
32024-09-23T13:13:09Z Saw new header hash=00000000000000000000f9892b8210cc52b3f71c1f37ffcfcecc2dab746b6084 height=862525
42024-09-23T13:13:09Z Saw new cmpctblock header hash=00000000000000000000f9892b8210cc52b3f71c1f37ffcfcecc2dab746b6084 peer=1
52024-09-23T13:13:10Z ERROR: ConnectBlock: CheckQueue failed
62024-09-23T13:13:10Z InvalidChainFound: invalid block=00000000000000000000f9892b8210cc52b3f71c1f37ffcfcecc2dab746b6084 height=862525 log2_work=95.170350 date=2024-09-23T13:12:13Z
72024-09-23T13:13:10Z InvalidChainFound: current best=0000000000000000000164dcfef37624f2cc6b177032bbca57631285c2cd0267 height=862524 log2_work=95.170337 date=2024-09-23T13:05:37Z
82024-09-23T13:13:10Z [error] ConnectTip: ConnectBlock 00000000000000000000f9892b8210cc52b3f71c1f37ffcfcecc2dab746b6084 failed, block-validation-failed
92024-09-23T13:13:10Z InvalidChainFound: invalid block=00000000000000000000f9892b8210cc52b3f71c1f37ffcfcecc2dab746b6084 height=862525 log2_work=95.170350 date=2024-09-23T13:12:13Z
102024-09-23T13:13:10Z InvalidChainFound: current best=0000000000000000000164dcfef37624f2cc6b177032bbca57631285c2cd0267 height=862524 log2_work=95.170337 date=2024-09-23T13:05:37Z
112024-09-23T13:13:16Z New outbound-full-relay v2 peer connected: version: 70016, blocks=862525, peer=27
122024-09-23T13:13:23Z New outbound-full-relay v1 peer connected: version: 70016, blocks=862525, peer=28
In this case it was possible to restart the node with -par=1, to output the actual failure:
02024-09-23T14:19:04Z [error] ConnectTip: ConnectBlock 00000000000000000000f9892b8210cc52b3f71c1f37ffcfcecc2dab746b6084 failed, mandatory-script-verify-flag-failed (Script evaluated without error but finished with a false/empty top stack element)
However it would also be useful to get that information in either case. The cause of the ConnectBlock failure here has currently been put down to hardware.