Chafing from Lulu bra?

Yesterday did a 22km trail run in a Lulu envital bra. It was raining so everything was very wet early on.

I didn’t feel or notice any discomfort, but did notice early stages of chafing/rash right in the middle of the sternum below the bra band.

Is this a sign the bra is too tight? Loose? Neither?

Yes it all was wet but come summer I’ll be sweating enough anyway! Haha

Last year I accidentally ran in a non-running Lulu bra and got really bad raw chafing in this exact spot - though it had “fully” healed and I’ve never experienced any bra chafing outside of this.

I feel I’ve been relatively lucky with not having chafing issues… and I know things like body glide exist but hoping I can still manage the root cause?!