phrases - "At the least" to start a sentence seems right but

The sentence I am trying to construct will be read with the assumption that finding that a bug exists in unfortunate. This is what I want to say, paraphrased:

We found a bug in the code. At the least, it causes this negative effect, but it might cause others.

My question is on the use of "at the least." The reason I am questioning this is because I have not heard this phrase very much. The two other similar phrases I have heard do not seem to convey the idea in the same way.

We found a bug in the code. At least, it causes this negative effect, but it might cause others.

When the reader gets past "at least," he or she will be in the mindset that a negative thing has happened (the bug was found), but there is a bright side. Generally, after a negative statement, "at least" is used to "look on the bright side" and mention a positive aspect of the situation. However, this is not what I am doing, so the sentence will read weirdly.

We found a bug in the code. At the very least, it causes this negative effect, but it might cause others.

Reflecting on the way that I am familiar with this phrase, I feel that, when the reader gets past "at the very least," he or she will think that I am about to suggest the least that we should do to fix the problem, but that is not what I am doing, so the sentence will read weirdly. Also, personally, I think this phrase is over-used and is a bit sensationalist with the "very" in there.

For those reasons, I feel "at the least" is the best option. However, I am still stuck on the fact that it is an uncommon phrase. This makes me hesitant to use it and makes me wonder whether it (or even "at the very least") is grammatically correct. Is this grammatically correct? If so, does it read so strangely that it rivals the magnitude to which the others read strangely?

I would appreciate most an answer concerning the phrase "at the least," but alternative ways to phrase the sentence would be helpful as well. Also, this is my first post, so any suggestions on my posting behavior/style would be helpful.