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If you are not using reference tags, the Edge side client must publish historic data in-order (synchronously) before live data resumes.  This This is because because Ignition will ignore writes to the tag if the timestamp on the tag change is older that the current value.

If you are using reference tags and have the Ignition Allow Back-fill Data disabled on the tag provider that will contain the reference tags, the Edge side client must publish historic data in-order (synchronously) before live data resumes. This is because because Ignition will ignore writes to the tag if the timestamp on the tag change is older that the current value.

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