If the channels are small, yes is noticeable when the onchain fees are fluctuating also. Are the "commit_fees" that affect this behavior. Read more here:

• https://bitcoin.stackexchange.com/questions/89232/why-is-my-spendable-msat-much-lower-than-msatoshi-to-us/89235#89235
• https://old.reddit.com/r/lightningnetwork/comments/cjtbjt/question_regarding_commit_fee/

Look in Thunderhub app, in total liquidity report and you will see where is going