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There appear to be 14 bytes of mysterious junk between the end of the final VLAN header and the beginning of the real IPv4 header - i.e., enough bytes to make up an extra Ethernet header, complete with an Ethernet type field value of 0x0800, for IPv4.

The is, for example 0x08 0x00 0x45 0x00, which are two bytes of 0x0800, the Ethernet type for IPv4, followed by one byte of 0x45, which is an IP header version of 4 and an IPv4 header length of 20 bytes (5 4-byte words) - the length of an IPv4 header without any options.

Is there any traffic on the Ethernet segment on which you did the capture other than traffic between Juniper networking equipment? If not, perhaps this is something weird that Juniper devices send, in some cases, when they know they're talking to fellow Juniper devices.