When configuring IPFIX export, MAC addresses are truncated to the first two bytes.

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Explanation: we were wrongly using the string representation of the MAC addresses instead of their binary representation. A MAC is 6 bytes, but when represented as a string, it's 2x6 characters + the ":" separators, which is 17 bytes.

In go-ipfix 0.12, this would just truncate to 6 bytes (6 bytes as string like "01:12:" = 2 MAC bytes) without causing more side effect or corrupting the buffer, because the buffer index was incremented exactly to the expected size (6 bytes): https://github.com/vmware/go-ipfix/blob/34201df9daa01865abac010657a54c8a7d09e67c/pkg/entities/record.go#L217

However since version 0.13, the way data is written to the buffer changed: https://github.com/vmware/go-ipfix/blob/3c6f32b463800cc84aeb27869b13dbe64a59dbcc/pkg/entities/ie.go#L682 - it's appended regardless of its size. Later on, there's a verification that the buffer size match exactly the expectation: https://github.com/vmware/go-ipfix/blob/3c6f32b463800cc84aeb27869b13dbe64a59dbcc/pkg/exporter/process.go#L467 - which would return an error in our case. This makes our tests failing with go-ipfix 0.13.