signature valid false randomly in claim search

This signature is valid. If I refresh it, then it works.

       "address": "bCjPhht755FuisQZqfhCoaEmrhWXH1xcPq",
        "amount": "0.01",
        "canonical_url": "lbry://@KhanAcademy#5/getting-started-with-khan-academy-kids#d",
        "claim_id": "d9c94bf123642eb6495c6ce3decfcfeeaf724887",
        "claim_op": "create",
        "confirmations": 14,
        "height": 734880,
        "is_channel_signature_valid": false,
        "meta": {
          "activation_height": 734880,
          "creation_height": 734880,
          "creation_timestamp": 1584730794,
          "effective_amount": "0.01",
          "expiration_height": 2837280,
          "is_controlling": true,
          "reposted": 0,
          "support_amount": "0.0",
          "take_over_height": 734880,
          "trending_global": 0.0,
          "trending_group": 0,
          "trending_local": 0.0,
          "trending_mixed": 32.263797760009766
        },
        "name": "getting-started-with-khan-academy-kids",
        "normalized_name": "getting-started-with-khan-academy-kids",
        "nout": 0,
        "permanent_url": "lbry://getting-started-with-khan-academy-kids#d9c94bf123642eb6495c6ce3decfcfeeaf724887",
        "short_url": "lbry://getting-started-with-khan-academy-kids#d",
        "signing_channel": {
          "channel_id": "5fc52291980268b82413ca4c0ace1b8d749f3ffb"
        },
        "timestamp": 1584730794,
        "txid": "2cdbdadae2fc42486f2de6960d3f6cd32fafc4858f9b25006a2932799a0ddf12",
        "type": "claim",
        "value": {
          "description": "Khan Academy Kids is an award-winning educational app for young learners ages two to seven. Watch this video to learn how to set up an account for your child and have them start learning. It\u2019s quick and easy, and will take no more than a few minutes. \n\nKhan Academy Kids is available on iPhone, iPad, Google Play, and Amazon. It\u2019s 100% free\u2014no ads, no subscriptions. \n\nDownload now!\nhttp://khan.co/YTKhanKids-AppleStore   \nhttp://khan.co/YTKhanKids-GooglePlay  \nhttp://khan.co/YTKhanKids-Amazon\n...\nhttps://www.youtube.com/watch?v=GbrtpAd-fVE\nNote: All Khan Academy content is available for free at (www.khanacademy.org)",
          "languages": [
            "en"
          ],
          "license": "Copyrighted (contact publisher)",
          "release_time": "1584725014",
          "source": {
            "hash": "b59414510c3f8bee8c112dcb089c82da929f7a289f07924bb7a08b9eef4f563458a58e05eb884638907268e2d51d2da6",
            "media_type": "video/mp4",
            "name": "getting-started-with-khan.mp4",
            "sd_hash": "e96ddb8926edc184e2c9d5577b56e3aaac5846f4b2b3d4b1b17e3fc0d950ea3789d156e007918e5bd68f9df22fa5ecf5",
            "size": "12131215"
          },
          "stream_type": "video",
          "tags": [
            "learning",
            "science",
            "online class",
            "online education",
            "online learning",
            "video class",
            "video tutorial",
            "education"
          ],
          "thumbnail": {
            "url": "https://thumbnails.lbry.com/GbrtpAd-fVE"
          },
          "title": "Getting started with Khan Academy Kids",
          "video": {
            "duration": 151,
            "height": 1080,
            "width": 1728
          }
        },
        "value_type": "stream"
      },

Start by reproducing the claim search for the supplied Khan Academy claim and compare the initial response with a refreshed request. Trace where is_channel_signature_valid is calculated, then verify that repeated searches consistently report the signature as valid when the claim data is unchanged.