public newer than the signature

[Ludwig Hügelschäfer]

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Hello,

the last weeks, when importing public keys I sometimes get:

"Öffentlicher Schlüssel %s ist %lu Sekunden jünger als die Unterschrift"

in english:

"public key %s is %lu second newer than the signature"

The indicated time interval is very large. What's running wrong? I tried
googling, but found nothing useful. I'm using gpg 1.4.9 on Mac OS X.

TIA

Ludwig
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