Present perfect tense + Simple past?

[azlieazlie]

Hi,

Can i use present perfect tense and simple past tense in one sentence?

"New risks have been updated in the risk registers, which they were presented and endorsed by the Committee last month."

My reasoning for use the said tenses:

- New risks have been updated in the risk registers = the info is still the same as the ones endorsed earlier by the Committee.

- Which they were presented and endorsed by the Committee last month = one-time action in the past with a time marker.

Thank you, sir.

[Alan]

Yes, but (delete 'they' from your sentence).